H.C.F and L.C.M

Q31. Find the H.C.F of (3 X 3² X 5 X 7⁴), (3² X 3³ X 5² X 7) and (3³ X 3⁵ X 5³ X 7⁵)
(a) 890
(b) 912
(c) 945
(d) 980

Q32. Find the H.C.F and L.C.M of 2/3, 8/9, 10/27 and 16/81
(a) 3/70, 71/5
(b) 2/81, 80/3
(c) 5/83, 83/7
(d) 5/99, 92/7

Q33. Two numbers are in the ratio 6 : 13. If their H.C.F is 5, find the numbers.
(a) 25, 65
(b) 30, 65
(c) 35, 85
(d) 40, 90

Q34. The H.C.F of two numbers is 5 and their L.C.M is 120. If one of the numbers is 40, find the other.
(a) 15
(b) 21
(c) 23
(d) 28

Q35. Four electronics devices make a beep after every 20 minutes, 40 minutes, 1 hour and 1½ hour respectively. All the devices beeped together at 12 noon. At what time will they beep together again?
(a) 4 PM
(b) 5 PM
(c) 6 PM
(d) 7 PM

Q36. Find the least number which when divided by 3, 4, 5, 6, 10 leaves the same remainder 3 in each case.
(a) 63
(b) 65
(c) 69
(d) 72

Q37. The L.C.M of (2² X 3³ X 5 X 11²), (2⁴ X 3 X 5² X 11), and (2 X 3 X 5³ X 11³) is
(a) 2² X 3⁴ X 5² X 11³
(b) 2³ X 3³ X 5³ X 11²
(c) 2⁴ X 3² X 5² X 11³
(d) 2⁴ X 3³ X 5³ X 11³

Q38. The sum of two numbers is 50. Their difference is 1/5 of their sum. The L.C.M is
(a) 54
(b) 55
(c) 57
(d) 60

Q39. The H.C.F and L.C.M of two numbers are 10 and 60 respectively. If the sum of the numbers is 50, then one of the number will be
(a) 5, 10
(b) 15, 20
(c) 20, 30
(d) 25, 35

Q40. The H.C.F of three numbers is 10. If they are in the ratio 1 :2: 3, then the numbers are
(a) 5, 10, 15
(b) 10, 20, 30
(c) 15, 30, 45
(d) 20, 40, 80

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