Question

Kims age was twice that of her sister. When you add Kim's age to her sisters age you, you get 36. How old is each sister?

Answer 1

Set kim's age to 2x. Set her sister's age to x. Now solve the equation:

2x+x=36
3x=36
x=12.

Remember, her sister's age was x, and x=12, so her sister is twelve. Kim's age is 12*2, so her age is 24.