Two cars start at the same time from opposite ends of a highway that is 175 miles long. One car is riding at 25 mph and the second car is riding at 45 mph. How long after they begin will they meet? Pick
A) 2
B) 2.5
C) 3
D) 3.5
E) 4

Rationale: "as cars are moving in opposite directions their speeds will be added . so their relative speeds : 45 + 25 = 70 mph total distance to be covered = 175 miles . time taken would be : 175 miles / 70 mph = 2.5 hours b is the answer ."
Answer: B