Question

The ratio of the present ages of two brothers is 1:2 and 5 years back, the ratio was 1:3. What will be the ratio of their age after 5 years?

Answer 1

ATQ,

the ratio between the present ages of two brothers is 1 : 2

let their ages be x and 2x respectively.

before 5 years, the ratio between their ages was 1 : 3

➡ (x - 5)/(2x - 5) = 1/3

by cross multiplying we get,

➡ 3(x - 5) = 1(2x - 5)

➡ 3x - 15 = 2x - 5

➡ 3x - 2x = -5 + 15

➡ x = 10 yrs

age of the two brothers are :-

• x = 10 yrs

• 2x = 2 × 10 = 20 years

hence, ratio of their ages after 5 years :-

= (10 + 5)/(20 + 5)

= 15/25 = 3/5

= 3 : 5 FINAL ANSWER

Answer 2

Answer :

Ratio of ages 5 years later  = 3:5

Step-by-step explanation :

Given that :

The ratio of the present ages of two brothers is 1 : 2.

5 years back, the ratio was 1 : 3

To Find :

The ratio of their ages after 5 years.

Solution :

Let the age of two brothers ages a & b, now.

$\dfrac{a}{b} = \dfrac{1}{2}$

Cross Multiplication :

⇒ 2a = b

5 years back the ratio was 1 : 3.

So,

$\dfrac{a-5}{b-5} = \dfrac{1}{3}$

Cross multiply :

⇒ 3(a-5) = b - 5

⇒ 3a - 15 = b - 5

⇒ 3a = b - 5 + 15

⇒ 3a = b + 10

Use the value of of b in 2a.

⇒ 3a = 2a + 10

⇒ 3a - 2a = 10

⇒ a = 10 years a's present age.

And,

2(20) = 20 years b's present age.

We have to find ratio,

So,

$\implies \dfrac{10+5}{20+5} = \dfrac{15}{25} = 3:5$

$\bigstar \textbf {\underline{\underline{Hence,The ratio of their age is 3:5.}}}$