HCF and LCM Quiz Set 013

Question 1

The product of LCM and HCF of two numbers is 3720? If one of the numbers is 62, what is the other?

A

60.

B

62.

C

61.

D

63.

Soln.
Ans: a

Product of two numbers is equal to the product of their LCM and HCF. So the other number is \$3720/62\$ = 60.

Question 2

What is the HCF of \${6/19}\$, \${13/14}\$ and \$2{2/5}\$?

A

\${1/1330}\$.

B

\${1/665}\$.

C

\${3/1330}\$.

D

\${2/665}\$.

Soln.
Ans: a

The HCF of numerators 6, 13 and 12 is 1. The LCM of denominators 19, 14 and 5 is 1330. So the required HCF of the given fractions is 1/1330 = \${1/1330}\$.

Question 3

Three cyclists are cycling in a circular track. They, respectively, take 5, 13 and 22 minutes to complete the circle once. After how many minutes will they all again meet at a single point?

A

1430 minutes.

B

2860 minutes.

C

715 minutes.

D

1431 minutes.

Soln.
Ans: a

The answer lies in finding the LCM of their times. The LCM of 5, 13 and 22 = 1430.

Question 4

What is the HCF of (19 × 7), (7 × 6) and (6 × 19)?

A

1.

B

2.

C

0.

D

3.

Soln.
Ans: a

The required HCF is product of the three numbers divided by their LCM. The LCM of 19, 7 and 6 is 798. So the required HCF = \${19 × 7 × 6}/798\$ = 1. Please note that LCM(n1, n2, n3) × HCF(n1 × n2, n2 × n3, n3 × n1) = n1 × n2 × n3.

Question 5

Two numbers are in the ratio 4 : 1. If their HCF and LCM are 4 and 16, which of these is the smaller number?

A

4.

B

8.

C

16.

D

2.

Soln.
Ans: a

Since the numbers are in an integral ratio, the LCM is equal to the larger number, and HCF is equal to the smaller number. So the smaller is 4. This Blog Post/Article "HCF and LCM Quiz Set 013" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Updated on 2019-08-18.