A boat goes 24 km upstream and 36 km downstream total time taken is 6 hours. If the boat goes 36 km upstream and 24 km

A boat goes 24 km upstream and 36 km downstream total time taken is 6 hours. If the boat goes 36 km upstream and 24 km downstream then the time taken is 6 1/2 hours. Find the speed of boat in still water?

(a)          9 km/hr

(b)          8 km/hr

(c)           12 km/hr

(d)          10 km/hr

Sol:

Subtracting both we get 60 km downstream at 5 hours

Speed of downstream = 12 km/hr

From 1 ⇒ for 36 km downstream = 3 hour

24 km upstream in 3 hours

Upstream = 8 km/hr

Speed of boat = 10 km/h