H.C.F & L.C.M. - Online Quiz



Following quiz provides Multiple Choice Questions (MCQs) related to H.C.F & L.C.M.. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - 10951168 when expressed in simplest form is?

A - 1516

B - 1316

C - 1726

D - 2526

Answer : A

Explanation

Q 2 - The smallest fraction, which each of 67, 514, 1021 will divide exactly, is?

A - 3898

B - 60147

C - 50294

D - 307

Answer : D

Explanation

Required fraction = L.C.M of 67, 514, 1021 = L.C.M of 6, 5, 10H.C.F of 7, 14, 21 = 307

Q 3 - The least number, which when divided by 48, 60, 72, 108 and 140 leaves 38, 50, 62, 98 and 130 as remainders respectively, is?

A - 11115

B - 15110

C - 15120

D - 15210

Answer : B

Explanation

Here (48 - 38) = 10, (60 - 50) = 10, (72 - 62) = 10, (108 - 98) = 10 & (140 - 130) = 10
Therefore Required number = (L.C.M  of 48,60,72,108,140) - 10 = 15120 - 10 =15110.

Q 4 - Three numbers are in the ratio 3:4:5 and their L.C.M is 2400. Their H.C.F is?

A - 10

B - 20

C - 30

D - 40

Answer : D

Explanation

Let the numbers be 3z, 4z, and 5z. then their L.C.M = 60z 
 So, 60z = 2400 or z = 40.
Therefore the numbers are (3 x 40), (4 x 40), (5 x 40).
Hence the required H.C.F = 40.

Q 5 - Let N be the greatest number that will divide 1305, 4665 and 6905 leaving the same remainder in each case. then the sum of the digits in N is?

A - 5

B - 4

C - 6

D - 8

Answer : B

Explanation

N = H.C.F of (4665 - 1305), (6905 - 4665), (6905 - 1305)
= H.C.F of 3360, 2240 and 5600 = 1120.
Sum of digits in N = (1 + 1 + 2 + 0) = 4.

Q 6 - Find the H.C.F. of 2/3, 2/5 and 2/7

A - 3/105

B - 2/105

C - 5/105

D - 7/105

Answer : B

Explanation

H.C.F. of given fractions =  (H.C.F.of denominators)/(L.C.M.of numerators)=2/105
(  H.C.F.of numerators    = 2  L.C.M.of denominators =105)

Q 7 - The ratio between the LCM and HCF of two numbers is 12:1. If the numbers be 48 and 64, find their LCM and HCF.

A - 192, 16

B - 144, 12

C - 120, 10

D - 48, 4

Answer : A

Explanation

Let the LCM & HCF be 12X & X respectively
LCM x HCF =12X x X=48x64
⇒X2= (48x64)/12⇒X=16
⇒HCF=16 & LCM=192

Q 8 - The sum of two numbers is 45 and difference is 1/9 of their sum. What is their L.C.M:

A - 100

B - 150

C - 200

D - 250

Answer : A

Explanation

Let the numbers be x and y . Then,
{x+y= 45  , x= (1/9*45)= 5} ⇒x = 25, y =20
L.C.M of 25 and 20 = (5*5*4)= 100

Q 9 - The ratio of two numbers is 15:11. Having their H.C.F as 13 ,numbers are:

A - 75, 55

B - 105, 77

C - 15,11

D - 195, 143

Answer : D

Explanation

Let the numbers be 15x  and 11x . Then , their H.C.F is x.
∴ x= 13 and so the numbers are (15*13, 11*13) i.e , 195, 143

Q 10 - Three numbers are in the ratio of 3:4 :5 , their L.C.M is 2400. Their H.C.F is :

A - 40

B - 80

C - 120

D - 160

Answer : A

Explanation

Let the numbers be 3x, 4x and 5x.
Then L.C.M =  60x
60x= 2400   ⇒ x= 40
∴ The numbers are 120, 160 and 200.
Clearly , their H.C.F is 40 
aptitude_hcf_lcm.htm
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