Help with Algebra Word Problem?

Question

I need help with a word problem on my homework it's:

"A speed boat traveled 60 miles with the current in 1 1/2 hours. The return trip took 2 hours against the current. What is the speed of the current?"

I know it's simple but I really need some help on this problem. Thanks!

Answer 1

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b= speed of boat in still water

c = speed of current

(time) x (speed) = distance and 1 1/2 hours = 1.5 hours

1st equation

1.5(b+c) = 60 (divide both sides by 1.5)

b + c = 40

2nd equation

2(b-c) = 60 ( divide both side by 2)

b - c = 30

put equations on top of each other

b + c = 40

b - c = 30 ( now subtract)

2c = 10

c = 5 miles per hour

substitute c=5 in to solve for b

b +5= 40

b = 35 miles per hour

some free videos to help with this at

http://www.kjaro.com/practice/category/72 ( linear systems - current questions )

Hope that helps!

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