Question

Mary's age is 10 years less than 2 times Joe's age. If the difference between their ages is 30, how old is Mary?

Answer 1

70

Explanation:

You want to know Mary's age if it is 10 years less than 2 times Joe's age, and the difference between their ages is 30.

Setup

We can write equations to describe the given relationships:

2j -m = 10

m -j = 30

Solution

Adding the two equations, we get ...

(2j -m) +(m -j) = (10) +(30)

j = 40 . . . . . . . . . . . . . . . . . . simplify (Joe is 40)

m = j +30 = 70 . . . . . . . . find Mary's age

Mary is 70 years old.

<95141404393>