Two cyclists start from two towns, A and B, which are 180 km apart, and move towards each other. The cyclist from A rides at 40 km/h, while the cyclist from B rides at 50 km/h. However, the cyclist from A starts 45 minutes earlier. Find the time (in hours, rounded to two decimals) after A's start when they meet.
Show answer & explanation
Correct answer: C
Explanation
Given:
Total distance = 180 km
Speed of A = 40 km/h
Speed of B = 50 km/h
A started 45 minutes earlier = 0.75 hours
Let the time of meeting after B starts be = t hours
Time taken by A = t + 0.75
Distance covered by A = 40(t + 0.75)
Distance covered by B = 50t
Total distance = 180
40(t + 0.75) + 50t = 180
40t + 30 + 50t = 180
90t + 30 = 180
90t = 150
t = 1.67
Time elapsed after A started = t + 0.75 = 1.67 + 0.75 = 2.42 hours