Question

Sixty-five percent of a number is $21$ less than four-fifth of that number. what is the number?

• A. 100
• B. 120
• C. 140
• D. 160

Answer 1

The correct option is C 140

let the number be ${}^{\prime }{x}^{\prime }$

Given:-

$65\%$ f $x=\frac{4}{5}\left(x\right)-21$

$\Rightarrow \frac{65}{100}x=\frac{4}{5}x-21$

$\Rightarrow \frac{13x}{20}-\frac{4x}{5}=-21$

$\Rightarrow \left[\frac{13x-16x}{20}\right]=-21$

$\Rightarrow \frac{3x}{20}=21$

$\Rightarrow x=7\times 20=140$

$\therefore x=140$