The current ages of Sonali and Monali are in the ratio 5 : 3. Five years from now, their ages will be in the ratio 10 : 7. Then Monali's current age is = ?

A. 3 years

B. 5 years

C. 9 years

D. 15 years

Answer: Option C

Solution(By Examveda Team)

Let,
⇒ Sonali's age = 5x
⇒ Monali's age = 3x
According to the question,
$$\eqalign{ & \Rightarrow \frac{{5x + 5}}{{3x + 5}} = \frac{{10}}{7} \cr & \Rightarrow \frac{{x + 1}}{{3x + 5}} = \frac{2}{7} \cr & \Rightarrow 7x + 7 = 6x + 10 \cr & \Rightarrow x = 3 \cr} $$
⇒ So, Monali's present age = 3x
= 3 × 3 = 9 years