A man can row 15 km/hr in still water. It takes him twice as long to row upstream as to row downstream. Find the rate of stream? a) 5 km/hr b) 10 km/hr c) 7.5 km/hr d) 6 km/hr e) 8 km/hr
Let the man’s upstream speed be x km/hour and downstream speed will be 2x
km/hour
Speed in still water = 1/2 (2x + x) = 3x/2 km/hour
3x/2 = 15
X = 10
Hence, his downstream speed = 20km/hour
Rate of stream = 1/2 (20-10) = 5km/hour
Answer: a)