Question

If $\frac{1}{8}+\frac{1}{10}=\frac{a}{b}$ , where $a$ and $b$ are positive integers and $\frac{a}{b}$ is in its simplest reduced form, then the value of $a$ is

• A. 2
• B. 9
• C. 18
• D. 40

Answer 1

Answer: (B)

9

Given, $\frac{1}{8}+\frac{1}{10}=\frac{a}{b}$

The L.C.M of $8$ and $10$ is $40$.

So, we have $\frac{5}{40}+\frac{4}{40}=\frac{a}{b}$

$\Rightarrow \frac{a}{b}=\frac{9}{40}$

Since the fraction is in its simplest form, $a=9$