I tried working this problem out and I know someone tried to help me earlier but I just dont understand it HELP!! Rusty has a boat goes 12 mi. an hour. Find the current speed of the river if he can go 3 mi. upstream in the same time as he goes 5 mi. downstream.

ok, distance= rate * time right?

yes, but it asks to find the current speed...so where does that come in to play?

I am not good with word problems at all :(

ok, well my rate upstream is 12-x and downstream is 12+ x where x is my speed of current

solve for time in the first equation i gave you and you have distance/rate= time

you know that the time for going upstream 3 miles, is equal to going to downstream 5 miles

so, 3/(12-x)=5(x+12) now just solve for x

ok, im working on it lol ill get back to you on this one

I got the current speed to be 12 miles per hour....is this correct?

no,

:(

i suck at this

what did you do to solve for x?

one second, i think i know what i did wrong

oh wow i am totally lost :( first i multiplied both sides by 12 -x and i got 36 - 3x = 60 - 5x / x + 12 is this right so far?

multiply both sides by the lcd of both fractions

yes now multiply by x +12

wait no its wrong

when multiplying 36 - 3x by x + 12 do I use the foil method?

:(

its not 35-3x! because qhen you multiply x-12 to both sides, it cancels on the left side

(x-12) * (3/12 -x)....the denominator cancels out but you still have to multiply 3 by x-12

no! thats the whole point of multiplying by x-12 so they cancel, see when you multiply you will have 3(x-12)/(x-12) now, the x-12 cancel out and you only have left

3

OMG!! I hate word problems......................

it's not the word problem, you need to practice your algebra...

no, i always have trouble with word problems. i know how to do algebra, but you dont understand...i have been working non stop on this home work assignment for 3 days straight....i am TIRED and my brain hurts....and word problems get me so confused that i make stupid mistakes in my algebra

yeah, i know im a tutor and i help out people, and i know how it stresses people

ok so if it cancels out and leaves 3 then you would end up with 3 = 5 / x + 12 correct?

yeah not multiply both sides by x+12

3x + 36 = 5 ???

umm multiply the x-12 to the 5 on the right side

it does not cancelt out in the right since the denominator of the right side is x+12

3 = 5x - 60 /x + 12

48 miles per hour!!!!!!

please tell me i am right

wait lol i havent done the work yet give me a minute

lol

yep!

YAY!! Thank you so much for helping me and not giving up on me!!! You are the best!!

no problem i love math!

i do too but i hate word problems lol

whats the use of math if we can't apply it to the world?

that is a very good point :)

I have ran into a big problem with this question. When I do this equation 3 / x-12 = 5 / x+12 x turns out to equal 48. But then if you do the equation this way: 3 / 12 - x = 5 / 12+x x turns out to equal 3 So which way is correct?

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