Today Mary’s father is four times as old as Mary. Ten years ago, he was 10 times as old. How old is Mary today?
Choose the correct choice from the following options
A) 11 B) 12 C) 13 D) 14 E) 15
Dad's age = 4M   10*(M-10) = 4M-10   6M = 90   M = 15   The answer is 15.
<result>E</result>
Today Mary’s father is four times as old as Mary. Ten years ago, he was 10 times as old. How old is Mary today?