Question

Kate is three years older than her sister. In two years Kate will be twice older. How old is Kate's sister now?

Answer 1

Kate's sister is 5

Explanation:

(k = kate's age)

(s = sister's age)

k = s + 3

k + 2 = 2s

Rearrange k + 2 = 2s into and plug it into the first equation

k = 2s - 2

2s - 2 = s + 3

2s - s = 3 + 2

s = 5