A motorboat takes 5 hours to travel 450 mi going upstream. The return trip takes 3 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Question

ganpat · Answer

x = speed of boat
y = speed of current

U = rate upstream
V = rate Downstream..

U = (x - y) = 450/ 5 = 90..

V = (x + y) = 450/ 3 = 150..

So rate of boat is still water  = (U + V)/ 2 = 240 /2 = 120 mph..

rate of current= 120 - y = 90 = 30 mph..

anonymous · Answer

I don't understand what you're saying

ganpat · Answer

i used the basic formula , Speed = distance / time.. 

Now we do not have only speed of boat.. But the boat is facing currents i.e. water speed. 

So when it is Upstream = x- y   .....  
and for downstream  = x + y

getting ??