Question

The ratio of two numbers is $4:5$. But, if each number is increased by $20$, the ratio becomes $6:7$. The sum of such numbers is

• A. $90$
• B. $95$
• C. $100$
• D. $60$

Answer 1

Answer: (A)

$90$

Let the number be $4x$ and $5x$.
According to the question,
$\Rightarrow \frac{4x+20}{5x+20}=\frac{6}{7}$
$\Rightarrow 28x+140=30x+120$
$2x=20$
$x=10$
$\Rightarrow Sum=4x+5x=9x$
$=9\times 10$
$=90$.