???? answer please!!!

Question

In his? motorboat, Bill Ruhberg travels upstream at top speed to his favorite fishing? spot, a distance of
112
112 ?mi, in
4
4 hr.? Returning, he finds that the trip? downstream, still at top? speed, takes only
3.5
3.5 hr. Find the rate of? Bill's boat and the speed of the current. Let x? = the rate of the boat in still water and y? = the rate of the current.

Answer 1

So, Marie, going upatream Bill averages 112/4 = 28 mph. Downstream, 112/3.5 = 32 mph.

 

Going upstream, he fights against the current. Going downstream, the current helps.

 

x - y = 28

x + y = 32

 

Adding the two equations together...

 

2x = 60

x = 30

 

30 + y = 32 or 30 - y = 28, so y = 2

 

The rate of the boat in still water is 28 mph and the current is a modest 2 mph.