Question

story problem

Answer 1

http://www.algebra.com/algebra/homework/word/travel/Travel_Word_Problems.faq.question.208013.html

Answer 2

Rowing at a constant rate, it takes 5 hours 45mi with the help of the current. It takes 9 hours to return AGAINST the current.

Let x = their speed and y = speed of the current.
Since s = d/t (speed = distance/time),
speed = 45/5 = 9
speed = x + y
x + y = 9

Using the info for going back,
speed = 45/9 = 5
speed = x - y
x - y = 5

We can use elimination to solve for this.

x + y = 9
- x - y = 5 adding
¯¯¯¯¯¯¯¯¯¯¯¯
2x = 14
x = 7

Since x + y = 9 and x = 7, y = 2

They're traveling at a constant speed of 7mph and the current is moving in the opposite direction at 2mph.