a boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 12 minutes . how long will it take to go 5 km in stationary water ?
"speed ( upstream ) = 2 / 1 = 2 kmhr speed ( downstream ) = 1 / ( 12 / 60 ) = 5 kmhr speed in still water = 1 / 2 ( 2 + 5 ) = 3.5 kmhr time taken in stationary = 5 / 3.5 = 1 hrs 25 min answer : c"
divide(5, divide(add(multiply(divide(1, 12), const_60), divide(2, 2)), const_2))