John was thrice as old as Tom 6 years ago. John will be 7/5 times as old as Tom in 6 years. How old is Tom today?
Pick one.
A) 7
B) 9
C) 11
D) 13
E) 15
J-6 = 3(T-6), so J = 3T-12   J+6 = 7/5 * (T+6)   5J + 30 = 7T + 42   5(3T-12) + 30 = 7T + 42   8T = 72   T = 9   The answer is 9.
<result>B</result>
John was thrice as old as Tom 6 years ago. John will be 7/5 times as old as Tom in 6 years. How old is Tom today?