A.) 16

B.) 9

C.) 8

D.) 7

E.) 5

x = number of years ago

23 - x = Bob's age "x years ago"

15 - x = Melanie's age "x years ago"

23 - x = 2(15 - x) {how many years was Bob's age twice Melanie's age}

23 - x = 30 - 2x {used distributive property on right side}

23 + x = 30 {added 2x to both sides}

x = 7 {subtracted 23 from both sides}

**D.) 7 years ago**, Bob was twice as old as Melanie

To check:

7 years ago, Bob was 23 - 7 = 16

7 years ago, Melanie was 15 - 7 = 8

He was twice as old as her

*© Algebra House*