# 2 Problems, need help, story problems!

• Oct 23rd 2007, 02:59 PM
MathMack
2 Problems, need help, story problems!
1.) suppose that you have a solution with 15% alcohol by volume and then you add to your orignial solution, an additional 20 milliteres of pure alcohol. If the resulting solution consists of 49% alcohol by volume, then how much alcohol do you have? (hint: Pick a variable for the amount of solution that you begin with, an dfind two different expressions for the final amount of alcohol.

2.) Suppose that youare planning a fence to surround a region with three sides, One side of this region is 60 feet long, but you don't know yet how long the other sides are. However you do know that one of these sides is twice as long as the other. Hint: draw a picture. If the total length of the fencing available is 300 feet, then how long can each side be?

THANK YOU FOR YOUR HELP, I'M STUPMED! PLEAS HELP!
• Oct 23rd 2007, 03:38 PM
galactus
Let x = the amount of alcohol you started with. You don't need two equations. Just one.

$0.15x+20=0.49(x+20)$

Solve for x.
• Oct 23rd 2007, 03:53 PM
MathMack
Thanks galactus, that's what I had but wasn't sure it was right, any idea on number 2? Thanks again!
• Oct 23rd 2007, 11:43 PM
Truthbetold
For number 2,
I think I got something.

x + 60 + y= 300
I doesn't specify whether which side is 2 times bigger so we will have y is 2 times bigger, which equals 2x=y

You mow have 2 equations for two unknown variables.
SUbsititute, solve for x, then solve for y.