A boatman travels 2 kilometres against the stream current in one hour and one kilometre with the current in ten minutes. How long would it take you to swim 5 kilometres in still water?
A. 40 minutes
B. 1 hour
C. 1 hr 15 mins
D. 1 hr 30 min
Answer:C
A boatman travels 2 kilometres against the stream current in one hour and one kilometre with the current in ten minutes. How long would it take you to swim 5 kilometres in still water?
A. 40 minutes B. 1 hour C. 1 hr 15 mins D. 1 hr 30 min
Explanation: Downstream rate = 1/10 x 60 km/hr = 6 km/hr,Upstream, the rate is 2 km/hr.In calm water, 1/2 (6 + 2) km/hr equals 4 km/hr,5/4 hr = 1 1/4 hr = 1 hr 15 min is the required time.