Std : 9 1Mental Maths Competition®

Set -3

1. 807

= ________

(a) 87.5 (b) 0.875

(c) 0.0875 (d) 8.75

2. 125 × 54 × 8 = ________(a) 54000 (b) 5400

(c) 45000 (d) 50400

3. Average of 52, 34, 43, 75,61 is ________(a) 49 (b) 51

(c) 55 (d) 53

4. The L.C.M. of two numberis 60. If one of the numberis 12 then the other numberis ________(a) 5 (b) 15

(c) 48 (d) 10

5. 1017² = ________(a) 1304289 (b) 1430289

(c) 1034289 (d) 1043289

6. 922² = ________(a) 800584 (b) 840085

(c) 805084 (d) 850084

7. 24.3 = ________(a) 1.2 (b) 0.18

(c) 1.6 (d) 1.8

8. The bridge A is 0.728 kmand bridge B is 1.52 kmlong. Find differencebetween their lengths.(a) 0.792 (b) 0.079

(c) 7.92 (d) 0.729

9. % of 200 = 40(a) 40 (b) 20

(c) 30 (d) 80

10. How do you write 5021

as

percentage.(a) 42 (b) 52

(c) 72 (d) 62

11. What is a cube of 8(a) 256 (b) 382

(c) 512 (d) 524

12. 400 + 80 = 30 × (a) 15 (b) 14

(c) 17 (d) 16

13. By what length 84.7 km is

longer than 54 21

km

(a) 30.2 (b) 30.3

(c) 31.8 (d) 31.2

14. Which of these numbers ismultiple of 15 & 7 both(a) 115 (b) 105

(c) 120 (d) 135

SECTION 1(Mental Maths Calculation)

Std : 9 2Mental Maths Competition®

Set -3

15. 63 × 3 21

=

(a) 220.55 (b) 202.5

(c) 220.05 (d) 220.5

16. 5³ – 5² = (a) 100 (b) 50

(c) 25 (d) 75

17. The sum of two integers is– 17. If one is 4, find the other.(a) 21 (b) 13

(c) –21 (d) –13

18. If x = 4, y = 2(– x)y + (y)x = (a) –32 (b) 16

(c) 32 (d) –16

19. Which decimal number is

the same as 53

(a) 0.6 (b) 0.4

(c) 0.5 (d) 0.2

20. A man buys a radio for ` 400and sells it at profit of 15%.He sold the radio for _____(a) 415 (b) 435

(c) 470 (d) 460

21. The sum of 1.8, 20.7 and38.917 is(a) 614.17 (b) 61.417

(c) 6.141 (d) 61.0417

22. 54 km/h = _____ m/s(a) 20 (b) 25

(c) 15 (d) 18

23. (–60) + (–12) × (5) × (– 3) =(a) 120 (b) –120

(c) 240 (d) –240

24. 40 : 16 :: x : 2Value of x is ________(a) 7 (b) 5

(c) 4 (d) 6

25. When a number is reducedby 7 it becomes 80% ofitself. Find the number(a) 45 (b) 32

(c) 40 (d) 35

26. If 61

of 54 + 15% of 140 =

x + 17 then x = ______(a) 11 (b) 14

(c) 13 (d) 12

27. Which of the following

number is greater than 43

?

(a) 0.78 (b) 0.72

(c) 0.69 (d) 0.64

Std : 9 3Mental Maths Competition®

Set -3

28. 103

+ 10004

=_______

(a) 0.0304 (b) 0.304

(c) 30.4 (d) 30.04

29. 58 – = – 311(a) –253 (b) –369

(c) 253 (d) 369

30. 4 times of 67 – 5 times of 49(a) 21 (b) 23

(c) 35 (d) 28

31. 31398 =

(a) )3139( (b) )3139(

(c) 8 )3139( (d) 8 )3139(

32. If a + b = 8, a² + b² = 34find a × b.(a) 7 (b) 16

(c) 12 (d) 15

33. 31

of 285 – 41

of 288 =

(a) 23 (b) 26

(c) 24 (d) 28

34. In what times will ̀ 50becomes ` 59 at 4½% p.a.(a) 3 years (b) 5 years

(c) 2 years (d) 4 years

35. 73

x + 2 = 29, x =

(a) 35 (b) – 63

(c) 63 (d) – 35

36. What is a percentagechange from 5,20,000 to78,000(a) 85% decrease (b) 15% decrease

(c) 85% increase (d) 15% increase

37. A number 42 is divided intotwo parts in the ratio 3:4.Find the product of thenumbers(a) 412 (b) 432

(c) 362 (d) 282

38. 12.5% of 224 = 4 × (a) 7 (b) 8

(c) 9 (d) 10

39. Area of square is 529 sq.m.Its perimeter is ________(a) 84 m (b) 94 m

(c) 74 m (d) 92 m

40. Cirumference of circle = d.Find the circumferencewhen = 3.14 and d = 9cm(a) 18.19 (b) 31.25

(c) 28.26 (d) 21.78

Std : 9 4Mental Maths Competition®

Set -3

SECTION 2(Mental Maths Concepts)

41. What is a distance travelledin 18 min at 70 km/hr ?(a) 21 km (b) 19 km

(c) 18 km (d) 23 km

42. Which of these numbers is

equivalent to 76

?

(a) 5442

(b) 5448

(c) 4836

(d) 5648

43. 16 tins of sweetcorn arebought for `512 and sold at`40 per tin. Find profit afterselling all the tins.(a) 20% (b) 32%

(c) 28% (d) 36%

44. A boy’s walking pacemeasures 50 cm. How manymeter has he walked aftertaking 48 paces.(a) 24 cm (b) 240 cm

(c) 240 m (d) 24 m

45. An angle is seven eight of itssupplement find its measure(a) 124° (b) 96°

(c) 84° (d) 56°

46. Half of a number is addedto 17 then the sum is 53.The number is (a) 72 (b) 74

(c) 68 (d) 64

47. An article costing ` 630 is

reduced by 301

for cash

payment, The cash downprice is _______(a) 615 (b) 625

(c) 612 (d) 609

48. The area of hall is 192m². Itslength is 24 m find its perimeter(a) 56 m (b) 68 m

(c) 64 m (d) 46 m

49. Ratio of Radii of two circlesis 5:7. Their circumference’sratio is ________(a) 25:49 (b) 24:42

(c) 49:25 (d) 31:54

Std : 9 5Mental Maths Competition®

Set -3

50. Two sums of money are inthe ratio 3:7, If the secondsum is 84, the first sum is____________(a) 24 (b) 36

(c) 18 (d) 42

51. In 4a

+ 2a

= 6, the value of a

is __________(a) 6 (b) 7

(c) 8 (d) 9

52. In a ABC AB + BC = 18 cmBC + CA = 28 cm, CA + AB= 36 cm. The perimeter ofABC is ________(a) 49 (b) 43

(c) 39 (d) 41

53. A sum of three consecutiveodd numbers is 75, find thesmallest of them(a) 21 (b) 23

(c) 19 (d) 25

54.35

71

51

mm

= m

(a) 12 (b) 15

(c) 8 (d) 14

55. 37 – [12 – {7 – (2 – 5 – 8)}] =(a) 31 (b) 24

(c) 43 (d) 19

56. Value of x in 8x

+ 41

= 8

(a) – 62 (b) 31

(c) – 31 (d) 62

57. In what time a sum willbecome double of itself at16% p.a. simple interest(a) 6 4

1 years (b) 7 21 years

(c) 8 41 years (d) 7 years

58. The three even consecutiveintegers whose sum is 108.The smallest of them is ___(a) 36 (b) 34

(c) 38 (d) 42

59. 12 taps can fill a tank in4 hrs. How much time willbe required for 3 taps to fillthe tank.(a)16 hrs (b) 9 hrs

(c) 8 hrs (d) 4 hrs

60. Find the vertex angle of anisosceles triangle if its baseangle is 40°(a) 100° (b) 140°

(c) 50° (d) 120°

Std : 9 6Mental Maths Competition®

Set -3

61. A fort has enough food for 840 soldiers for 45 days. If after5 days 140 soldiers left the fort, how long will the food lastnow?(a) 45 days (b) 46 days (c) 42 days (d) 48 days

62. A big pipe can fill an aquarium in 31

hr. A small pipe takes

1 41

hr to fill the same aquarium. How long will both pipe take

to fill the aquarium together.

(a) 15 hrs (b) 151915

hrs (c) 151915

min (d) 17131

min

63. When 15 is added to 2 21

of a number, the answer is 3 times

the number. Find the number.(a) 24 (b) 18 (c) 22 (d) 30

64. Numbers 40, 36, 32, 24, 2x + 6, 3x + 1, 9, 8, 6,5 arewritten in descending order and if their median is 11, then xequal to ________(a) 3 (b) 12 (c) 5 (d) 8

65. If A:B = 2:5, B:C = 5:3 and C:D = 3:4 the A:D equal to _______(a) 2 : 1 (b) 1 : 2 (c) 4 : 3 (d) 2 : 3

SECTION 3 (Mental Maths Challenge)

Std : 9 7Mental Maths Competition®

Set -3

66. The largest box of shoes contains 768 pieces. The next size boxcontains 192 pieces. They also sell a box with 48 pieces and onesmallest box. Based on this pattern, how many pieces are therein the smallest box?(a) 12 (b) 10 (c) 8 (d) 14

67. A man borrows ` 650 and agrees to repay with a total interest of` 40 in 3 installments. Each installment being less than thepreceding by ` 15. What should be his 3rd installment?(a) 215 (b) 230 (c) 245 (d) 250

68. 40 circular plates each of radius 14 cm and thickness 41

cm

are placed one above another to form a right circular cylinder.Find total surface area of the cylinder so formed?(a) 880 cm² (b) 808 cm² (c) 888 cm² (d) 800 cm²

69. What should comes in place of the question marks in thefollowing number series.

5, 11, 24, 51, 106, , 440

(a) 205 (b) 215 (c) 223 (d) 217

70. In a soccer tournament the average of goals scored in first fivegames was 7.2. The average of his next four games was 6.5. Ifthere were 9 goals scored in the tenth game. What was theoverall average?(a) 7.4 (b) 7.1 (c) 7.6 (d) 7.8

Std : 9 8Mental Maths Competition®

Set -3

71. If a tyre rotates at 200 revolutions/ min when the truck istravelling at 40 km/hr. What is the circumference of tyre?(a) 0.0033 km (b) 0.33 km (c) 3.33 km (d) 0.033 km

72. If the numerator of a fraction is increased by 300% and thedenominator of the fraction is increased by 200%, the resultant

fraction is 398

. Find the fraction.

(a)4

13(b) 13

2(c) 15

7(d) 21

8

73. In a series 4, 7, 10, 13, ........ what will be 16th term.(a) 47 (b) 49 (c) 48 (d) 51

74. Ram and Sham graduated from university together. Shamhas earned half what Ram earned for 5 years. Ram spent1/4 of money, Sham spent 1/5 money for those 5 years. Shamhas ` 12000 after 5 years. Find savings of Ram in 5 years.(a) ` 22500 (b) ` 252000 (c) ` 522000 (d) ̀ 226000

75. Four glasses of juice be extracted from half a watermelon. Iftwo glasses can hold 250 ml of juice, how many watermelonsare needed to make seven liters of juice?(a) 10 (b) 12 (c) 7 (d) 14

Std : 9 9Mental Maths Competition®

Set -3