The speed of a boat in still water is 21 km/hr and the rate of current is 8 km/hr. The distance travelled downstream in 13 minutes is	Choose the correct option:
A) 1.6 km	B) 2 km	C) 6.3 km	D) 4 km	E) None of these
Explanation:   Speed downstreams	=(21 + 8)kmph   = 18 kmph.   Distance travelled	= (29 x 13/60)km   = 6.3km   Option 6.3 km
<result>C</result>
The speed of a boat in still water is 21 km/hr and the rate of current is 8 km/hr. The distance travelled downstream in 13 minutes is