Hi, I need help with this problem...like ASAP. If anyone can help me...please :-) Here it is: How many gallons of a 3% salt solution must be mixed with 50 gallons of a 7% solution to obtain a 5% solution?

Question

anonymous · Answer

Short Answer: 50
do you want the long anwser? that explains it step by step...

anonymous · Answer

Hi Lolly, Yes please. Thank you.

anonymous · Answer

$$\frac{ 50*0.03 + x*0.07 }{ 50+x } = 0.05$$

anonymous · Answer

Thank you FredrickV

anonymous · Answer

Long Answer:
 We can set up an equation:
 .03x + .07 * 50 = .05(x+50), where x is the number of gallons of 3% salt solution to be added
 
Multiply both sides by 100 to make things easier
 3x +7*50 = 5(x+50)
 3x + 350 = 5x + 250
 subtract 3x from both sides
 350 = 2x + 250
 subtract 250 from both sides
 100 = 2x
 divide both sides by 2
 50 = x
 or 
x = 50

anonymous · Answer

Wow! Lolly, that's just what I was looking for...thank you thank you thank you.

anonymous · Answer

http://www.wolframalpha.com/input/?i=%2850%E2%88%970.03%2Bx%E2%88%970.07%29%2F%2850%2Bx%29%3D0.05

anonymous · Answer

no prob!:)