Two boys starts from the same place walking at the rate of 5 kmph and 5.5 kmph respectively in the same direction. What time will they take to be 8.5 km apart?
17 hr
14 hr
12 hr
19 hr
Explanation:
Relative speed = 5.5 - 5 = 0.5 kmph [because they walk in the same direction]
distance = 8.5 km
time =$\dfrac{distance}{speed} = \dfrac{8.5}{0.5}$ = 17hr