Question

The ratio of As salary to Bs was 4 : 5. As salary is increased by 10% and Bs by 20%, what is the ratio of their salaries now?

• A. 11:15
• B. 11:55
• C. 11:66
• D. 11:33

Answer 1

The correct option is A 11:15

Let the salary of $B$ be $x$ .

So Salary of $A$ is $\frac{A}{x}=\frac{4}{5}$

Solving,Salary of $A=\frac{4x}{5}$

Now, if salary of $A$ is increased by $10\%$, the new salary of $A$ is $\frac{4x}{5}+\frac{4x}{5}\times 10\%$

$=0.8x+0.8x\times \frac{10}{100}$

$=0.8x+0.8x\times 0.1$

$=0.8x+0.08x=0.88x$

New Salary of $B=x+x\times 20\%$

$=x+x\times \frac{20}{100}$

$=x+\frac{x}{5}=\frac{5x+x}{5}=\frac{6x}{5}=1.2x$

Hence the ratio of their new salaries are

$\frac{A}{B}=\frac{0.88x}{1.2x}=\frac{0.88}{1.2}=\frac{0.88\times 100}{1.2\times 100}=\frac{88}{120‬}=\frac{22}{30}=\frac{11}{15}$

Hence the ratio is $11:15$