Question

How do you set up this equation?
Ann's age is seven tenths of Bill's age. In 4 years Ann's age will be eight-elevenths of Bill's age. How old is Bill now.

Answer 1

x = bill's age
7x/10 = ann's age

Answer 2

Bill's age = x
Anne's age = (7/10)x

4 years later (both have aged 4 years):
Anne's age + 4 = (8/11)(Bill's age + 4)
(7/10)x + 4 = (8/11)(x + 4)
x = 40