A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
Choose the correct choice
A) 30 minutes	B) 45 minutes	C) 1 hour	D) 1 hour 15 min	E) None
Sol.   Rate downstream = [16/2= 
<gadget id="calculator">16/2</gadget>
<output>8</output>
8 kmph; Rate upstream= [16/4= 
<gadget id="calculator">16/4</gadget>
<output>4</output>
4 kmph.   ∴ Speed in still water= 1/2(8+4) kmph = 6 kmph.   Answer 1 hour 15 min
<result>D</result>
A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?