IB Math Studies Year II – Midterm Review Questions KEY 1. (a) (b) 1 × 14 × 8 sin110° 2 = 52.62278676 m2 = 52.6 m2 (3s.f) Area = (M1) (A1) sin C 8 sin 110 (or equivalent) 18 8 sin 110 sin C = 18 C = 24.68575369 C = 24.7° (3s.f.) Note: Accept all answers obtained from all appropriate methods, given to the correct degree of accuracy. (M1) (A1) [4] 2. (a) Compound interest 8% per year (A1) (A1) (b) Year Value at beginning of year Value at end of year 1st CHF 500 CHF 540 2nd CHF 540 CHF 583.20 3rd CHF 583.20 CHF 629.86 4th CHF 629.86 CHF 680.25 5th CHF 680.25 CHF 734.67 (A1) 6th CHF 734.67 CHF 793.44 (A1) [4] 3. (a) BC = 482 57 2 2(48)(57) cos117 (or equivalent) 89.7 m (3 s.f.) (b) 1 1 ab sinC = (48)(57)sin117° 2 2 2 = 1220 m (3 s.f.) Area of ABC = (M1) (A1) (M1) (A1) [4] IB Questionbank Mathematical Studies 3rd edition 1 4. (a) CAˆ B = 180 – 2×23° = 134° (M1) (A1) (C2) (b) AB sin 23 (M1) 15 sin 134 Note: Follow through with candidate’s answer from (a) 15 sin 23 sin 134 AB = 8.147702831... = 8.15 (3 s.f.) AB = (A1) (C2) [4] 5. (a) III (A1) (b) I (A1) (c) II (A1) (d) IV (A1) [4] 6. Note: Award (A1) for each pair of correct entries in parts (a) and (c). A list of numbers with no set brackets is acceptable. (a) A B = {1, 3, 4, 7, 8, 9} (b) A B (c) A = {1, 3, 4, 7, 8, 9} A C = {6, 7} (A C) B = {3, 6, 7, 9} C = {9} (A1)(A1)(A1) (C3) (A1) (C1) (A1) (A1) (A1)(A1) (C4) [8] 7. (a) u1 + 3d = 12 u1 + 9d = 42 (A1)(A1) (A1)(A1) (C4) Note: Award (A1) for left hand side correct, (A1) for right hand side correct. IB Questionbank Mathematical Studies 3rd edition 2 (b) 6d = 30 d=5 u1 = –3 (A1) (A1) (M1)(A1) (C4) Note: Follow through (ft) from candidate's equations. [8] 8. (a) (x – 3)(x + 1) Note: Award (A0)(A1) if the signs are reversed. (A1)(A1) (C2) (b) A(1, 0), B(3, 0) (A1)(A1) (C2) (c) x = 1 or x = ( 1 3) = 1 or x = 2 ( 2) =1 2(1) (A1)(A1) (C2) Note: Award (A1) for x = and (A1) for 1. (d) C(1, –4) (A1)(A1) (C2) [8] 9. (a) Angle A = 90 – 5 = 85°. (M1)(A1) (C2) (b) BC2 = 62 + 82 – 2 × 8 × 6 cos(85°) so BC = 91.6330487 = 9.57 (3 s.f.) (M1)(A1) (A1) (C3) (c) BC sin (A) AC sin (B) 6 sin (85 ) sin (B) = = 0.6244093654 9.572515275 Angle B = sin–1(0.6244093654) = 38.6° Note: Allow 38.7° if obtained using 9.57. (M1) (A1) (A1) (C3) [8] IB Questionbank Mathematical Studies 3rd edition 3 10. (a) (b) U U B A B A C (c) C (d) U B A (A2)(A2) U B A C C Note: Award (A0), (A0), (A2) ft, (A2) ft if consistently reversed. and (A2)(A2) are [8] 11. (a) I = 0.04 × 2000 × 18 = 1440 Euros Total amount = I + 2000 = 3440 Euros. (b) 2000 1 (M1)(A1) (M1)(A1) (C4) 18 12 0.036 12 = 3819.72 = 3820 Euros, to nearest Euro. (M1)(A1) (A1) (A1) (C4) [8] 12. (a) Put x = 0 to find y = –2 (M1) Coordinates are (0, –2) (A1) (C2) Note: Award (M1)(A0) for –2 if working is shown. If not, award (M0)(A0). IB Questionbank Mathematical Studies 3rd edition 4 (b) Factorise fully, y = (x – 2) (x + 1). (A1)(A1) y = 0 when x = –1, 2. (A1)(A1) Coordinates are A(–1, 0), B(2, 0). (A1)(A1) (C6) Note: Award (C2) for each correct x value if no method shown and full coordinates not given. If the quadratic formula is used correctly award (M1)(A1)(A1)(A1)(A1)(A1). If the formula is incorrect award only the last (A1)(A1) as ft. [8] 13. (a) (b) R2 = 36 so R = 6 cm Use cosine rule. AB2 = 62 + 62 – 2 (M1)(A1) (C2) 6 6 cos (110 ) (M1)(A1)(ft) AB2 = 96.6 AB = 9.83 cm (A1)(ft) OR 6 AB sin (35 ) sin (110 ) (M1)(A1)(ft) AB = 9.83 cm (A1)(ft) OR 110 55 2 1 AB 2 sin (55 ) = 6 (M1)(A1)(ft) AB = 9.83 (A1)(ft) (C3) Note: If this method is used, then the 1 AB must be evident to 2 obtain the (M1) and the first (A1) requires the 55 and the 6 to be correct. (c) L= 36 or 6 or 10.6 cm (A1) (C1) [6] 14. (a) AC2 = 9 + 9=18 AC = 18 (= 4.24) IB Questionbank Mathematical Studies 3rd edition (M1) (A1) (C2) 5 (b) 18 Area of triangle ACD = 0.5 4.5 sin 25 (M1)(A1) = 4.03 (c) (A1) (C3) Area of triangle ABC = 0.5 3 3 = 4.5 cm2 (M1)(A1) Total area = 8.53 (A1) (C3) [8] 15. (a) correct incorrect correct 1 4 2 5 incorrect 3 4 3 5 2 4 correct incorrect (b) (i) 2 5 = (ii) 3 4 2 4 (A2) (C2) 3 2 5 4 Note: Award (A1) for each correct product. (A1)(A1) 12 (= 0.6) 20 2 5 3 10 1 4 1 10 (A1) (C3) 1 = (0.25) 4 Note: Award (A1) for (A1)(A1)(A1) (C3) 2 5 1 3 seen and (A1) for 4 10 1 seen. 10 [8] IB Questionbank Mathematical Studies 3rd edition 6 16. (a) (A4) (C4) Note: Award (A1) for some indication of scale on the y-axis. Award (A1) for at least one asymptote drawn. Award (A1) for each of the two (smooth) branches. The left hand branch must pass through 0. One branch should be above the horizontal asymptote and the other below but if the asymptote is not drawn, then there should be little or no overlap in heights of the branches. If this condition is not fulfilled, award (A1)(A0) for the curve. (b) (i) Horizontal asymptote y = 3 (ii) Vertical asymptote x = 1 (A1) (A1)(ft) (C2) Equations for x and y must be seen, (ft) if reversed. [6] 17. (a) sin 50 sin 30 AC 400 (M1)(A1) Note: Award (M1) for using sine rule with values from the problem, (A1) for correct substitution. AC = 613 (3 s.f.) IB Questionbank Mathematical Studies 3rd edition (A1) (C3) 7 (b) Perimeter = 400 + 613 + 788 = 1801m Time in seconds = 1801 1000 1.8 (A1)(ft)(A1) Note: Award (A1) for the perimeter, (A1) for finding the time in seconds, and last (A1)(ft) for finding the time in minutes. The time in minutes follow through from the time in seconds. Time in minutes = 1000 50 ( 16.7 to 3 s. f .) 60 3 (A1)(ft) (C3) [6] 18. (a) a 8 1 2 a=4 (A1) OR 2 1 a 2 a=4 (b) (A1) (C1) 7 1 8 2 0.0625 (M1)(A1)(ft) 0.0625 (M1)(A1)(ft) (C2) OR 2 8 (c) 5 1 2 1 2 12 1 1 2 1 16.0 (3 s. f ) ( 4095/256) (M1)(A1)(ft) (A1)(ft) (C3) Note: Award (M1) for using correct formula and correct substitution, (A1) for correct answer (15.99...). (A1) for correct answer to 3 s.f. [6] IB Questionbank Mathematical Studies 3rd edition 8 19. (a) 6x + 3 – 6 + 2x = 13 8x = 16 (M1) x=2 (b) (x + 3) (x – 1) (c) x = 1.64575.. (A1) (C2) (A1)(A1) (C2) x = 1.65 (A2) (C2) Note: If formula is used award (M1)(A1) for correct solution. If graph is sketched award (M1)(A1) for correct solution. [6] 20. (a) 19 seedlings (A1) (C1) (b) (i) median 88 cm (A1) (ii) 1st quartile 78 cm, 3rd quartile 103 cm (both correct) (A1) (C2) 112 63 = 49 cm (A1) (C1) (c) Note: Accept 63 and 112 both seen, if they appear in the answer space for (c) or under working for (c) (but not just implied or written on the box plot). (d) (C2) Notes: Box with correct median and quartiles marked. (A1)(ft) Both correct whiskers joined to box with straight lines (A1)(ft) (C2) Allow maximum errors of 2. Perfectly ruled lines are not essential. [6] IB Questionbank Mathematical Studies 3rd edition 9 21. (A1) (A1) (A1) (A1) (A1) (A1) Notes: (C6) For any number entered exactly once, in the correct position, award (A1) if incorrect award (A0). If all numbers entered in all regions award (A0). If any number is entered in more than one region, penalize that number as follows: (i) If none of the regions is correct award (A0) (ii) If one of the regions is correct but other appearances of that number are in the COMPLEMENT of the correct set, award (A0) the first time this is seen. (iii) If one of the regions is correct but other appearances of that number are in a SUBSET of the correct set award (A0) the first time this is seen. Apply each of (ii) and (iii) at most once and award ft marks when the error is seen repeatedly, however, (ii) and (iii) may not both be applied to the same number and if both these errors are present with more than one number involved, follow through cannot be used until both penalties have been applied. [6] 22. (a) d = –7 (b) S50 = (A1) (C1) 50 (2(124) + 49(–7)) 2 Note: (M1) for correct substitution. IB Questionbank Mathematical Studies 3rd edition (M1) 10 = –2375 IB Questionbank Mathematical Studies 3rd edition (A1)(ft) (C2) 11 (c) 124 – 7(k – 1) < 0 (M1) k > 18.7 or 18.7 seen (A1)(ft) k = 19 (A1)(ft) (C3) Note: (M1) for correct inequality or equation seen or for list of values seen or for use of trial and error. [6] 23. (a) 0.965 (A1) (C1) (b) y = 1.15x + 0.976 (A1) for 1.15x (A1) for +0.976 (A1)(A1) (C2) (c) y = 1.15 (7) + 0.976 (M1) Chemistry = 9.03 (accept 9) (A1)(ft) (C2) Note: Follow through from candidate’s answer to (b) even if no working is seen. Award (A2)(ft). (d) the correlation coefficient is close to 1 OR strongly correlated variables OR 7 lies within the range of physics marks. (R1) (C1) [6] 24. (a) (x − 5) (x + 2) (A1)(A1) Note: Award (A1) for (x + 5)(x−2), (A0) otherwise. If equation is equated to zero and solved by factorizing award (A1) for both correct factors, followed by (A0). (C2) (b) (i) (ii) −3, −2, −1, 0, 1, 2, 3 Notes: Award (A2) for all correct answers seen and no others. Award (A1) for 3 correct answers seen. (A1)(A1) −26,−7, 0, 1, 2, 9, 28 Notes: Award (A2) for all correct answers seen and no others. Award (A1) for 3 correct answers seen. If domain and range are interchanged award (A0) for (b)(i) and (A1)(ft)(A1)(ft) for (b)(ii). (A1)(A1) (C2) (C2) [6] IB Questionbank Mathematical Studies 3rd edition 12 25. (a) To double, interest = 3000 3000 = (A1) 3000 4 n 100 Note: For substituting into the simple interest formula (M1) n = 25 years (A1)(ft) Note: (A1) for 3000 on one side of equation if not seen separately. For interest of 6000 award (M1)(A1)(ft) for answers of 50 years. (b) 6000 = 3000 1 3.5 200 (C3) 2n (M1)(A1) Note: (M1) for substituting values into a compound interest formula, (A1) for correct values with a variable for the power. n = 20 years (A1) Note: If n used in formula instead of 2n, can allow as long as final answer is halved to get 20. (C3) [6] 26. (a) (b) FV = 8000 (1.0125)60 Note: (M1) for substituting in compound interest formula, (A1) for correct substitution (M1)(A1) €16857 only (A1) (C3) 8000 (1.0125)n = 9058.17 Note: (M1) for equating compound interest formula to 9058.17 (M1) n =10 correct answer only (A1) So 30 months, (ft) on their n Note: Award (C2) for 2.5 seen with no working (A1)(ft) (C3) [6] IB Questionbank Mathematical Studies 3rd edition 13 27. (a) 20 = u1 + 3d 32 = u1 + 7d (A1) (A1) Note: Award (A1) for each equation, (A1) for correct answer. OR d= 32 20 4 (A1)(A1) Note: Award (A1) for numerator, (A1) for denominator. d=3 (b) (A1) (C3) 10 10 (2 × 11 + 9 × 3) or (11 + 38) (M1)(A1)(ft) 2 2 Note: Award (M1) for correct substituted formula, (A1) for correct substitution, follow through from their answer to part (a). OR 11 + 14 + ... + 38 (M1)(A1)(ft) Note: Award (M1) for attempt at the sum of a list, (A1)(ft) for all correct numbers, follow through from their answer to part (a). = 245 (A1)(ft) (C3) [6] 28. (a) 3 (b) −1/3 (c) Substituting (6, 7) in y = their mx + c or equivalent to find c. y= (d) (A1) (C1) (ft) from (a) 1 x 9 or equivalent 3 (1.5, 8.5) (A1)(ft) (C1) (M1) (A1)(ft) (C2) (A1)(A1)(ft) Note: Award (A1) for 1.5, (A1) for 8.5. (ft) from (c), brackets not required. (C2) [6] IB Questionbank Mathematical Studies 3rd edition 14 29. (a) (A1)(A1)(A1) (C3) Note: Award (A1) for a labeled Venn diagram with appropriate sets. (A1) for 7, (A1) for 8 and 5. (b) P (Spanish / one language only) = 8 20 (M1)(A1)(ft) 8 5 20 20 Note: Award (M1) for substituted conditional probability formula, (A1) for correct substitution. Follow through from their Venn diagram. = 8 (0.615, 61.5%) 13 (A1)(ft) OR P (Spanish / one language only) = 8 (A1)(ft)(M1) 8 5 Note: Award (A1) for their correct numerator, (M1) for correct recognition of regions. Follow through from their Venn diagram. = 8 (0.615, 61.5%) 13 (A1)(ft) (C3) [6] 30. Financial penalty applies in part (a) (a) FP I = 1200 1 7.2 600 5 12 1200 (M1)(A1) I = 518.15 euros (A1) (C3) Notes: Award (M1) for substitution in the compound interest formula, (A1) for correct substitutions, (A1) for correct answer. If final amount found is 1718.15 and working shown award (M1) (A1)(A0). (b) 1200 r 5 100 r = 8.64 % (% sign not required) 518.15 = IB Questionbank Mathematical Studies 3rd edition (M1)(A1)(ft) (A1)(ft) (C3) 15 Note: Award (M1) for substitution in the simple interest formula, (A1)(ft) for correct substitution, (A1)(ft) for answer. [6] 31. (a) = (b) = 91 (0.607, 60.6 % , 60.7%) (A1)(A1) (C2) 150 Note: Award (A1) for numerator, (A1) for denominator. 111 37 , 0.74, 74% 150 50 (A1)(ft)(A1) (C2) Note: Award (A1)(ft) for their numerator in (a) +20 provided the final answer is not greater than 1. (A1) for denominator. (c) 16 (0.176, 17.6%) (A1)(A1)(ft) (C2) 91 Note: Award (A1) for numerator and (A1)(ft) for denominator. Follow through from their numerator in (a) provided answer is not greater than 1. [6] 32. (A1)(A1)(A1) (A1)(A1)(A1) (C6) Note: Award (A1) for each number placed once in the correct region. Accept equivalent forms for numbers. [6] 33. (a) (i) 8.5 (cm) (A1) (ii) 120° (A1) IB Questionbank Mathematical Studies 3rd edition 16 (iii) (b) 30° BC sin120 (A1) (C3) 8.5 (M1)(A1)(ft) sin 30 Note: Award (M1) for correct substituted formula, (A1) for correct substitutions. BC = 14.7 17 3 2 (A1)(ft) (C3) [6] 34. (a) (x + 8)2 = (x + 7)2 + x2 Note: Award (A1) for a correct equation. (A1) x2 + 16x + 64 = x2 + 14x + 49 + x2 Note: Award (A1) for correctly removed parentheses. (A1) x2 – 2x –15 = 0 Note: Accept any equivalent form. (A1) (C3) (b) x = 5, x = –3 (A1)(ft)(A1)(ft) (C2) Notes: Accept (A1)(ft) only from the candidate’s quadratic equation. (c) 30 cm (A1)(ft) (C1) Note: Follow through from a positive answer found in part (b). [6] 35. Financial penalty applies in parts (b) and (c). (a) 0.88×16000 OR 0.12×16000 OR 1920 14080 (b) 1.6407×5.25×14080 121280.54 USD Note: Follow through from their answer to part (a). (c) 12 × FP FP 1 0.8739 13.73 AUD (M1) (A1) (C2) (M1) (A1)(ft) (C2) (M1) (A1) (C2) Note: If division used in part (b) and multiplication used in part (c), award (M0)(A0) for part (b) and (M1)(A1)(ft) for part (c). [6] IB Questionbank Mathematical Studies 3rd edition 17 36. Unit penalty applies in part (b). 4 (M1) 9 ˆ D) 100 + their (AB (M1) 126° (A1) (C3) Notes: Accept an equivalent trigonometrical equation involving angle ABD for the first (M1). Radians used gives 100°. Award at most (M1)(M1)(A0) if working shown. BD = 8 m leading to 127°. Award at most (M1)(M1)(A0) (premature rounding). (a) ˆD sin AB (b) AC2 = 102 + 92 – 2 × 10 × 9 × cos(126.38...) (M1)(A1) Notes: Award (M1) for substituted cosine formula. Award (A1) for correct substitution using their answer to part (a). UP AC = 17.0 m (A1)(ft) (C3) Notes: Accept 16.9 m for using 126. Follow through from their answer to part (a). Radians used gives 5.08. Award at most (M1)(A1)(A0)(ft) if working shown. [6] 37. (a) 108 54 , 0.432, 43.2% 250 125 (A1)(A1) (C2) Note: Award (A1) for numerator, (A1) for denominator. (b) (c) 25 (0.236, 23.6%) (A1)(A1) (C2) 106 Note: Award (A1) for numerator, (A1) for denominator. 71 (0.418, 41.8%) (A1)(A1) (C2) 170 Note: Award (A1) for numerator, (A1) for denominator. [6] 38. (a) (b) –4, –3, –2, –1, 0, 1, 2 (A1) (C1) Note: Award (A1) for correct numbers, do not penalise if braces, brackets or parentheses seen. 4 (0.571, 57.1%) 7 IB Questionbank Mathematical Studies 3rd edition (A1)(ft)(A1)(ft) (C2) 18 Notes: Award (A1)(ft) for numerator, (A1)(ft) for denominator. Follow through from part (a). Note: There is no further penalty in parts (c) and (d) for use of denominator consistent with that in part (b). (c) (d) 1 (0.143, 14.3%) 7 Note: Follow through from part (a). (A1)(ft) (C1) 1 (0.143, 14.3%) (A1)(ft)(A1)(ft) (C2) 7 Note: Award (A1)(ft) for numerator, (A1)(ft) for denominator. Follow through from part (a). [6] 39. (a) (b) 0 16 1 22 2 19 (M1) 80 Note: Award (M1) for substituting correct values into mean formula. 1.75 (A1) (C2) An attempt to enumerate the number of goals scored. (M1) 2 (A1) (C2) IB Questionbank Mathematical Studies 3rd edition 19 (c) 2 1.75 × 100 1.75 14.3 % (M1) (A1)(ft) (C2) Notes: Award (M1) for correctly substituted % error formula. % sign not required. Follow through from their answer to part (a). If 100 is missing and answer incorrect award (M0)(A0). If 100 is missing and answer incorrectly rounded award (M1) (A1)(ft)(AP). [6] 40. (a) 1 (one) (A1) (C1) Note: 6, {6} or {1} earns no marks. (b) 1, 3, 5, 7, 9, 11 (A1) (C1) Note: Do not penalise if braces, parentheses or brackets are seen. (c) (A1)(A1)(ft)(A1)(ft)(A1)(ft) (C4) Notes: Award (A1) for the empty set A B C . Award (A1)(ft) for the correct placement of 6, 5, 1 and 3. Award (A1)(ft) for the correct placement of 2, 4, 12, 7, 9, 11, 8. Award (A1)(ft) for the correct placement of 10. Follow through from part (b). [6] IB Questionbank Mathematical Studies 3rd edition 20 41. (a) x= 4 2 x=2 (M1) (A1) OR dy = 4 – 2x dx x=2 (M1) (A1) (2, 7) or x = 2, y = 7 (A1) (C3) Notes: Award (M1)(A1)(A0) for 2, 7 without parentheses. (b) (i) C labelled in correct position on graph (A1) (C1) (ii) 3 = 3 + 4x – x2 Note: Award (M1) for correct substitution of y = 3 into quadratic. (M1) (x =) 4 (A1) (C2) OR Using symmetry of graph x = 2 + 2 (M1) Note: Follow through from their x-coordinate of the vertex. (x =) 4 (A1)(ft) (C2) [6] IB Questionbank Mathematical Studies 3rd edition 21 42. (a) r= 36 1 108 3 (A1) (C1) Note: Accept 0.333. (b) u1 1 3 7 = 36 (M1) Note: Award (M1) for correct substitution in formula for nth term of a GP. Accept equivalent forms. u1 = 78732 (A1)(ft) (C2) Notes: Accept 78700. Follow through from their common ratio found in part (a). If 0.333 used from part (a) award (M1)(A1)(ft) for an answer of 79285 or 79300 irrespective of whether working is shown. 78732 1 (c) 118096 = 1 3 k (M1)(M1) 1 1 3 Notes: Award (M1) for correct substitution in the sum of a GP formula, (M1) for equating their sum to 118096. Follow through from parts (a) and (b). OR 1 Sketch of the function y = 78732 1 3 1 1 3 Indication of point where y = 118 096 k (M1) (M1) OR 78 732 + 26 244 + 8748 + 2916 + 972 + 324 + 108 + 36 + 12 + 4 = 118 096 (M1)(M1) Note: Award (M1) for a list of at least 8 correct terms, (M1) for the sum of the terms equated to 118096. k = 10 (A1)(ft) (C3) Notes: Follow through from parts (a) and (b). If k is not an integer, do not award final (A1). Accept alternative methods. If 0.333 and 79285 used award (M1)(M1)(A1)(ft) for k = 5. If 0.333 and 79300 used award (M1)(M1)(A0). [6] IB Questionbank Mathematical Studies 3rd edition 22 43. (a) 45000 + (5 – 1)1750 (M1)(A1) Note: Award (M1) for substituted AP formula, (A1) for correct substitutions. = 52000 USD (A1) (C3) Notes: If a list is used, award (M1) for recognizing AP, award (A1) for seeing 52000 in their list, (A1) for final answer. (b) 10 (2(45000) + (10 – 1)(1750)) (M1)(A1) 2 Notes: Award (M1) for substituted AP formula, (A1)(ft) for correct substitutions. Follow through from their common difference used in part (a). = 528750 USD (A1)(ft) (C3) Notes: Accept 529000. If a list is used, award (M1) for recognizing sum of AP, (A1) for seeing 60750 included in the sum or 528750 in a cumulative list. [6] 44. (a) (i) (ii) (b) area = 0 2 6 0 1 = 3 y= (M1) 2 , 0.333 6 (A1) (C2) 1 x+2 (A1)(ft) (C1) 3 Notes: Follow through from their gradient in part (a)(i). Accept equivalent forms for the equation of a line. 6 1.5 (A1)(M1) 2 Note: Award (A1) for 1.5 seen, (M1) for use of triangle formula with 6 seen. = 4.5 (A1) (C3) [6] IB Questionbank Mathematical Studies 3rd edition 23
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