Question

A woman is 43 years old, and her daughter is 15 years old. How many years will it be before the woman’s age is just twice her daughter’s?

Answer 1

W = 43 = present woman’s age

D = 15 = present daugter’s age

W - D = 43 - 15

W - D = 28

Add D to both sides

W = D + 28

Woman is 28 yrs older of daugter.

Woman will be twice older of daugter when:

W = 2 D

So:

W = 2 D

Replace W = D + 28 in this equation

D + 28 = 2 D

Subtract D to both sides

28 = D

D = 28

Woman will be twice older of daugter when daugter be 28 yrs old.

Present daugter’s age = 15

28 - 15 = 13

After 13 yrs woman will be twice older of her daughter.

Proof:

After 13 yrs woman will be 43 + 13 = 56 yrs old

Daughter will be 15 + 13 = 28 yrs old

56 / 28 = 2