Question

A boat traveled 126 miles downstream and back. The trip downstream took 6 hours. The trip back took 42 hours. What is the speed of the boat in still water? What is the speed of the current?

Answer 1

Answer:

The answer is

Speed of the boat in still water= 12mph

Speed of current= 9mph

Step-by-step explanation:

let x= speed of the boat in still water

let y= speed of current

DATA WE HAVE

with current  

rate- x+y        

time- 6 hours

distance- 126 miles

rate= 126/6= 21

against current

rate- x-y

time- 42hr

distance- 126 miles

126/42= 3

Now, we add these two equations vertically.

x-y=3

+

x+y=21            

2x = 24

Now we divide each side by 2

2x/2   24/2

x= 12

The speed of the boat in still water is 12mph

NOW WE HAVE HALF OF THE ANSWER

if x+y= 21

then

12+y=21

subtract 12 from both sides

y=9

The speed of the current is 9mph

Checking)

12+9=?21

21=21

12-9=?3

3=3

I hope this helped! If you have any questions, dm me on insta celinesaydawi