A train traveled the first d miles of its journey it an average speed of 60 miles per hour, the next d miles of its journey at an average speed of y miles per hour, and the final d miles of its journey at an average speed of 160 miles per hour. If the train’s average speed over the total distance was 98 miles per hour, what is the value of y?  Answers:
A) 68  B) 84  C) 90  D) 120  E) 125

Rationale: average speed = total distance traveled / total time taken 3 d / d / 60 + d / y + d / 160 = 98 solving for d and y , 15 y = 11 y + 480 4 y = 500 y = 125 answer e
Answer: E