Question

LCM of the denominators in the fractions $\frac{3}{16}$ and $\frac{7}{20}$ is

• A. 20
• B. 320
• C. 80

Answer 1

The correct option is C 80

$\underset{–}{ConceptUsed}$:
LCM of two numbers can be obtained by multiplying all the factors having highest powers.

$\underset{–}{Method}$:
16 can be written as $16=2\times 2\times 2\times 2$ and 20 can be written as $20=2\times 2\times 5$.

Taking the factors with highest powers common, we get
$2^4$ from 16 and $5^1$ from 20.

Multiplying them, we get $2^4\times 5=80$ as the required LCM.