A boat takes 4 hours to go 20 miles upstream.It can go 32 miles downstream in same time.Find the rate of the current and the rate of the boat in still water.

Question

asked Sep 19, 2016 224k views

2 Answers

Robert Fleming · Answer 1 · 2016-09-19T19:56:08+0000

Upstream: It goes about 5 mph b/c 20 miles/4 hours= 5 mph Downstream:It goes about 8 mph b/c 32 miles/ 4 hours=8 mph Hope I helped! :-)

Hardian · Answer 2 · 2016-09-23T01:19:29+0000

Let

x---------> the rate of the boat in still water in mph

y--------> the rate of the current in mph

we know that

Upstream

$rate=(20)/(4) \\\\ rate=5mph$

x-y=5 equation

Downstream

$rate=(32)/(4) \\\\ rate=8mph$

x+y=8 equation

Adds equation
and equation

$x-y=5\\ x+y=8\\ -----\\ 2x=13\\ x=6.5mph$

Find the value of y

$x+y=8\\ y=8-x\\ y=8-6.5\\ y=1.5 mph$

therefore

the answer is

the rate of the boat in still water is

the rate of the current is