Question

Lindsey has two sisters. The sum of the girls' ages is 13. The product of their ages is 36. How old is each sister?

Answer 1

The product of their ages is 36

The sum of the girls age is 13

two sister=?

13 by 36

26

Answer 2

x+y=13
x=13-y — (1)
xy=36 — (2)

Sub (1) into (2)
y(13-y)=36
y^2-13y+36=0
y=9 or 4 (quadratic formula)

Sub y=9,
x=4

Sub y=4,
x=9