Question

the age of som and hari are in ratio5:7. after 4 years from now thr ratio will be 3:4 .find the present age ?​

Answer 1

Answer:

Step-by-step explanation:

Answer 2

ANSwer:-

Present age of Som = 20 years and Hari = 28 years.

$\rule{100}2$

Explanation-

Let present age of Som be "5M" years and 

present age of Hari be "7M" years.

Four years from now the ratio of their ages will be 3:4

After 4 years,

• Age of Som = (5M + 4) years

• Age of Hari = (7M + 4) years

According to question,

$\implies\:\sf{\dfrac{5M\:+\:4}{7M\:+\:4}\:=\:\dfrac{3}{4}}$

Cross-multiply them

$\implies\:\sf{ 4(5M + 4)\: = \:3(7M + 4)}$

$\implies\:\sf{20M\: +\: 16 \:= \:21M\: +\: 12}$

$\implies\:\sf{20M\: - \:21M \:= \:12\: - \:16}$

$\implies\:\sf{20M \:-\: 21M\: = \:- 4}$

$\implies\: \sf{- M \:= \:- 4}$

$\implies\:\sf {M\: = \:4}$

Therefore,

Present age of Som = 5M

⇒ 5(4)

⇒20 years

Present age of Hari = 7M

⇒ 7(4)

⇒ 28 years

∴ Present age of Som is 20 years and

present age of Hari is 28 years.

$\rule{100}2$

 Verification-

From above calculations we have M = 4

Substitute value of M in this:-

$\dfrac{5M\:+\:4}{7M\:+\:4}\:=\:\dfrac{3}{4}$

=> $\dfrac{5(4)\:+\:4}{7(4)\:+\:4}\:=\:\dfrac{3}{4}$

=> $\dfrac{20\:+\:4}{28\:+\:4}\:=\:\dfrac{3}{4}$

=> $\dfrac{24}{32}\:=\:\dfrac{3}{4}$

=> $\dfrac{3}{4}\:=\:\dfrac{3}{4}$