Question

The age of Anjali and Ankit are in the ratio 5 : 7 .Four years now , the ratio of their ages will be 3 : 4. Find their present ages.​

Answer 1

Ratio of their ages = 5:7

Let anjalis age be = 5x

Let Rajus age be = 7x

ATQ

5x + 4/ 7x + 4 = 3/4                                     (3:4 = 3/4)

4(5x +4) = 3(7x + 4)

20x + 16 = 21x + 12

-12 + 16 = 21x - 20x

4 = x

Anjali's age = 5x

                    = 5 x 4

                    = 20 years

Ankit's age = 7x

                   = 7 x 4

                   = 28 years

Hope it helps :D

Answer 2

$Let \: Anjali's \: present \: age = 5x \: years$

$Ankit's \: present \: age = 7x \: years$

$four \: years \: later \: Anjali's \: age \: = (5x + 4)years$

$Ankit \: age \: = (7x + 4) \: years$

According to the question , we have

$\: \: \: \: (\frac{5x + 4}{7x + 4} ) = \frac{3}{4}$

By cross multiplication , we have

$4(5x + 4) = 3(7x + 4)$

$=> 20x + 16 = 21x + 12$

$=> 16 - 12 = 21x - 20x$

$=> 4 = x$

Therefore, Anjali's present age = 5x years

$= (5 \times 4) \: years \: = \: 20 \: years$

and Ankit present age = 7x years

$= (7 \times 4) \: years \: = 28 \: years$