A man takes 3 hours 45 minutes to row a boat 15 km downstream of a river and 2 hours 30 minutes to cover a distance of 5 km upstream. Find the speed of the current. Choose the correct option.
A) 1 km/hr
B) 2 km/hr
C) 3 km/hr
D) 4 km/hr
E) None of these
Explanation:   First of all, we know that   speed of current = 1/2(speed downstream - speed upstream) [important]   So we need to calculate speed downstream and speed upstream first.   Speed = Distance / Time [important]   Speed upstream =(15/3 3/4)km/hr   =15×4/15=4km/hr   Speed Downstream = (5/2 1/2)km/hr   =5×2/5=2km/hr   So speed of current = 1/2(4−2)   =1km/hr   Option 1 km/hr
<result>A</result>
A man takes 3 hours 45 minutes to row a boat 15 km downstream of a river and 2 hours 30 minutes to cover a distance of 5 km upstream. Find the speed of the current.