Question

Plz answer this friends

It takes a boat 3 hours to travel down a river from point A to point B, and 5 hours to travel up the river from B to A. How long would it take the same boat to go from A to B in still water?

Answer 1

Answer:

x speed of boat in still water

y speed of current

down river speed = x+y

upstream speed = x-y

Distance = same upstream and downstream

d=rt

3(x+y)=5(x-y)

3x+3y=5x-5y

2x=8y

x=4y

distance = 3(x+y)

but x=4y

distance = 3(4y+y)

=15y

speed in still water = 4y

time = d/r

=15y/4y

=3.75 hours

Time in still water = 3.75 hours