Question

the ratio of present ages of two brothers is 4 is to 5. after 10 years the ratio of their ages would be 6 is to 7 find the age of the elder brother after 15 years

Answer 1

Hii Mate !!

Solution :

Let present ages of two brothers be 4x and 5x.

After 10 years ages of two brothers will be : ( 4x + 10 ) and ( 5x + 10 ).

According to the given question :

The ratio of ages of two brothers after 10 Years will be = 6 : 7

So,

4x + 10 / 5x + 10 = 6 / 7

7 ( 4x + 10 ) = 6 ( 5x + 10 )

28x + 70 = 30x + 60

30x - 28x = 70 - 60

2x = 10

x = 5

Ages of two brothers are 4x and 5x , substitute the value of x in 4x and 5x .

=> 4*5 and 5*5. = 20 and 25 years respectively.

Hence,

Age of elder brother is 25 years and age of youngest brother is 20 year's.

After 15 years age of elder brother = 25 + 15 = 40 year's.


Hope it helps ♥

By Rishi403

BeBrainly.

Answer 2

Given, the present ages of two brothers is in the ratio 4 : 5

So, let their present ages be 4x and 5x

After 10 years, age of smaller brother = 4x + 10 and age of elder brother = 5x + 10

After 10 years, the ratio of their ages becomes 6 : 7


According to the question,

$\dfrac{4x + 10}{5x + 10} = \dfrac{6}{7}$

➾ 7(4x + 10) = 6(5x + 10)

➾ 28x + 70 = 30x + 60

➾ 70 - 60 = 30x - 28x

➾ 10 = 2x

➾ $\dfrac{10}{2}$ = x

➾ 5 = x




Age of elder brother after 15 years ➾ 5x + 15

➾ 5 × 5 + 15

➾ 25 + 15

➾ $\underline{40 \: years}$