If two trains are 120 miles apart and are traveling toward each other at constant rate of 30 miles per hour and 40 miles per hour, respectively, how far apart will they be 1 hour before they meet? Choose the correct option:
A) 10
B) 30
C) 40
D) 50
E) 70

Rationale: they would meet in 120 / 70 = 12 / 7 hours 1 hour earlier 5 / 7 hours distance between trains = total distance - ( distance covered by train a + distance covered by train b ) = 120 - ( 5 / 7 ( 40 + 30 ) ) [ distance of a = 5 / 7 * 40 ; like wise distance by b ] = 70 km answer : e
Answer: E