Question 328468
Molly's age = 2x

Anita's age = x

Sum of the square of their ages = (2x)^2 + x^2

Equate to 80 and solve for x.

(2x)^2 + x^2 = 80

4x^2 + x^2 = 80

5x^2 = 80

x^2 = 80/5

x^2 = 16

Let sqrt = square root for short

sqrt[x^2] = sqrt[16]

x = 4

Anita is 4 years old.

Molly is 2*4 years old or 8.