Question

Edith’s age is 1/4 of Ronald’s age. In how many years will Edith’s age be 1/3 of Ronald’s age if Edith is 20 years old?

Answer 1

10

Explanation:

x = Edith's age = 20 years

y = Ronald's age

x = 20 = y/4

y = 20×4 = 80 years

in z years we have

(x + z) = (y + z)/3

(20 + z) = (80 + z)/3

3(20 + z) = 80 + z

60 + 3z = 80 + z

60 + 2z = 80

2z = 20

z = 10

in 10 years Edith's age will be 1/3 of Ronald's age.

then Edith will be 30, and Ronald will be 90.

30 = 90/3

correct.