Question

julie and eric are going a constant speed down stream 24 miles for 4 hours at the same rate they go upsteam 24 miles for 6 hours, what is the rate of the current?

Answer 1

Which formula will we use?

d = ?

Answer 2

im thinking d=rt

Answer 3

Yes, now r can get complicated ....

upstream we are going x - y

and down stream we are going x + y

does this make sense?

Answer 4

yes

Answer 5

the first equation is

24 = 4(x + y)

can you get the second equation?

24 = ???

Answer 6

24=6(x-y)

Answer 7

so 4(x +y)=6(x-y)?

Answer 8

Yes, but I do not think we can solve this with x's and y's how about

24 = 4x + 3y
24 = 6x - 6y

and multiply the first equation by 2 to obtain

48 = 8x + 6y
24 = 6x - 6y

and then eliminate the y's to obtain

72 = ???

what is x???

Answer 9

i think the current is 1 mph

Answer 10

Do you see that

72 = 14x?