Question

A motorboat takes 5 hours to travel 100 mi going upstream. The return trip takes 2 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?

Answer 1

Rate upstream 100/5 rate downstream 100/2 so the average would be still water

Answer 2

??????

Answer 3

t = d/r

Answer 4

Calculate the average of the two trips.

Answer 5

5 = 100/(x-y)

Answer 6

I am hoping we can do this all the way through so I can learn it. I know we are supposed to make a distance, time, and rate table. And that x and y will stand for the rate of the boat in still water and the rate of the current.

Answer 7

for reference: @BlossomCake has a structured assignment that requires him to show his work using a table in a specific format...
http://openstudy.com/study#/updates/5692f2b8e4b0f78e197fe60d
I'd help but I'm about to fall asleep

Answer 8

Thanks, @inkyvoyd. :)

Answer 9

Can anyone help?? @retirEEd @mthompson440

Answer 10

upstream
5 = 100/(x-y)

Answer 11

Can you explain this?

Answer 12

A motorboat takes 5 hours to travel 100 mi going upstream
5 = 100/(x-y)
t = d/r

Answer 13

I don't understand the table format, so set it up and start filling it out so I can see if it is correct.

Answer 14

Okay, what are you using x and y to stand for?

Answer 15

let rate of boat in still water be x mph
rate of current be y
downstream speed = x+y
upstream rate = x-y

Answer 16

upstream
5 = 100/(x-y)
5(x-y)=100
5x-5y=100
x-y=20

Answer 17

So, you mean:

Answer 18

do the same for downstream

2= 100/(x+y)

Answer 19

Do I include the 100 miles in the table??

Answer 20

2(x+y)=100
2x+2y=100
x+y=50

Answer 21

2x=20+50
2x=70
x=35

Answer 22

y=15
2(x+y)=100
x+y=50

Answer 23

Is what I put in the distance column correct?

Answer 24

Maybe this is better, but it looks really good so far...