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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.
Q 1 - Find L.C.M and H.C.F of 0.63, 1.05 and 2.1.
Answer : D
Explanation
Making the same number of decimal places, the given numbers are 0.63, 1.05 and 2.10. without decimal places, these numbers are 63, 105, and 210 Now, H.C.F of 63, 105 and 210 is 21 so H.C.F of 0.63, 1.05 and 2.1 is 0.21 L.C.M of 63, 105 and 210 is 630 so L.C.M of 0.63, 1.05 and 2.1 is 6.30
Answer : B
Explanation
Given numbers are 1.08, 0.36 and 0.9. H.C.F of 108, 36 and 90 is 18. H.C.F of given numbers is 0.18.
Q 3 - The least number, which when divided by 12,15,20 and 54 leaves in each case a remainder of 8, is?
Answer : B
Explanation
Required number = (L.C.M of 12, 15, 20, 54) + 8 = 540 + 8 = 548.
Q 4 - Three numbers are in the ratio 3:4:5 and their L.C.M is 2400. Their H.C.F is?
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 - A rectangular courtyard 3.78 meters long and 5.25 meters wide is to be paved exactly with square titles all of the same size. What is the largest size of the tile which could be used for the purpose?
Answer : A
Explanation
Largest size of the tile = H.C.F of 378 cm and 525 cm = 21 cms.
Q 6 - The L.C.M. of two numbers is 72. Their H.C.F. is 12. If one number is 12, the other is
Answer : D
Explanation
Let the other number be X HCF*LCM=Product of two numbers 12*72=24*X ⇒X=(12*72)/24=36
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.
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 - Having H.C.F and L.C.M of two numbers as 21 and 4641 respectively. If one of the numbers is in between 200 and 300, then the two numbers are :
Answer : D
Explanation
Let the numbers be 21 a and 21 b, where a and b are co-primes. Then ,21 a* 21 b= (21* 4641)⇒ab= 221. Two co-primes with product 221 are 13 and 17. ∴ Numbers are (21*13, 21*17) , i.e (273,357)
Q 9 - H.C.F and L.C.F of two numbers x and y are 3 and 105 respectively. If x+y=36 then figure out 1/x + 1/y.
Answer : D
Explanation
We have X *y =3 *105 ⇒ xy = 315 ∴ x+y/xy =36/315 = 4/35 ⇒ 1/y+1/x = 4/35 ⇒ 1/x+1/y = 4/35.
Answer : A
Explanation
L.C.M of 8, 16,40 , 80 is 80. 7/8 = (7/8 *10/10 ) = 70/80 , 13/16 = (13/16*5/5)= 65/80 ,31/40 = (31/40* 2/2 )= 62/80,63/80 Clearly ,70/80 > 65/80 >63/80 >62/80 . Hence, 7/8 is the largest.