Question

If $\frac{1}{8!}+\frac{1}{9!}=\frac{x}{10!}$ , find $x$.

• A. $90$
• B. $100$
• C. $80$
• D. $95$

Answer 1

Answer: (B)

We have $\frac{1}{8!}+\frac{1}{9\times 8!}=\frac{x}{10\times 9\times 8!}$
Therefore $1+\frac{1}{9}=\frac{x}{10\times 9}$
or $\frac{10}{9}=\frac{x}{10\times 9}$
So, $x=100$.