Question

the age of Sudha was 5/2 times as old as her younger sister Sumi in 2055 b.s. and the age of Sudha will be 10 years less than twice the age of Sumi in 2070 b.s. find the birth year of Sumi.

Answer 1

The birth year of Sumi is
`2045`

Explanation:

Let

x------> the age of Sudha in 2055

y-----> the age of Sumi in 2055

we know that

`x=2.5y` -----> equation A

`(x+15)=2(y+15)-10` -----> equation B

Substitute equation A in equation B and solve for y

`(2.5y+15)=2(y+15)-10`

`(2.5y+15)=2y+30-10`

`2.5y-2y=30-10-15`

`0.5y=5`

`y=10`

Find the value of x

`x=2.5(10)=25`

The birth year of Sumi is

`2055-10=2045`