100+ HCF and LCM Questions for SBI PO, SO, Clerk Pdf - 1

Question: 1

Find the greatest number of five digits which becomes exactly divisible by 10, 12, 15 and 18 when 3769 is added to it.

(A) 99811

(B) 98911

(C) 99011

(D) 99911

Ans: D

L.C.M. of 10, 12, 15 and 18 = 540.

Dividing (99999 + 3769) by 540, the remainder is 88.

∴ Required number = 99999 - 88 = 99911.

Question: 2

Which of the following has most number of divisors?

(A) 99

(B) 101

(C) 176

(D) 189

Ans: C

99 = 1 × 3 × 3 × 11

101 = 1 × 101

176 = 1 × 2 × 2 × 2 × 11

182 = 1 × 2 × 7 × 13.

So, divisors of 99 are 1, 3, 9, 11, 33 and 99.

divisors of 101 are 1 and 101

divisors of 176 are 1, 2, 4, 8, 11, 16, 22, 44, 88 and 176

divisors of 182 are 1, 2, 7, 13, 14, 26, 91 and 182.

Hence, 176 has the most number of divisors.

Question: 3

The H.C.F. and L.C.M. of two numbers are 84 and 21 respectively. If the ratio of the two numbers is 1 : 4, then the larger of the two numbers is

(A) 48

(B) 84

(C) 92

(D) 96

Ans: B

Let the numbers be x and 4x.

Then, x × 4x = 84 × 21

⇔ x2 = $$({84 × 21} / {4})$$

⇔ x = 21.

Hence, large number = 4x = 84.

Question: 4

Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case.

(A) 4

(B) 7

(C) 9

(D) 11

Ans: A

Required number = H.C.F. of (91 - 43), (183 - 91) and (183 - 43)

                          = H.C.F. of 48, 92 and 140 = 4.

Question: 5

The product of two numbers is 4107. If the H.C.F. of these numbers is 37, then the greater number is

(A) 101

(B) 111

(C) 134

(D) 185

Ans: B

Let the numbers be 37a and 37b.

Then, 37a × 37b = 4107 ⇒ ab = 3.

Now, co-primes with product 3 are (1, 3)

So, the required numbers are (37 × 1, 37 × 3) i.e., (1, 111).

∴ Greater number = 111.

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