Question

Two boats started to move towards each other from two docks, located 30 miles apart. One boat moved at a speed of 2.5 miles per hour, the other moved twice as fast. How soon will the boats meet?

Answer 1

4 hours

Explanation:

Answer 2

Time taken for the boats to meet will be given by:
time=(distance)/(speed)
relative speed=(speed of boat A+speed of boat B)
speed of boat A=2.5 mph
speed of boat B=2(2.5)=5 mph
thus
relative speed=(5+2.5)=7.5 mph
distance=30 miles
thus
time=30/7.5=4 hours
thus the earliest they can meet is 4 hours