Question

Jane is 5 times older than her sister. In 3 years, Jane’s sister will be 1/4 her age. Find the ages now

Answer 1

The present age of Jane is 45 years old and present age of her sister is 9 years old

Solution:

Let the present age of Jane be "x"

Let the present age of her sister be "y"

Jane is 5 times older than her sister

present age of Jane = 5(present age of her sister)

x = 5y ---------- eqn 1

In 3 years, Jane’s sister will be 1/4 her age

Age of sister after 3 years = 3 + y

Age of jane after 3 years = 3 + x

Age of sister after 3 years = 1/4(age of jane after 3 years)

$3 + y = \frac{1}{4}(3 + x)$

Substitute eqn 1 in above equation

$3 + y = \frac{1}{4}(3 + 5y)\\\\12 + 4y = 3 + 5y\\\\5y - 4y = 12 - 3\\\\y = 9$

Substitute y = 9 in eqn 1

x = 5(9)

x = 45

Thus present age of Jane is 45 years old and present age of her sister is 9 years old