SOLUTION: This problem stumped my girlfriend and I please help How many gallons of a 4% acid solution should be mixed with 20 Gallons of a 10% acid solution to obtain a mixture that is 5%

Question 120409: This problem stumped my girlfriend and I please help
How many gallons of a 4% acid solution should be mixed with 20 Gallons of a 10% acid solution to obtain a mixture that is 5% acid?
Please show work that way I can see what I was doing wrong...
Thank you
Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
the concentration multiplied by the volume of solution gives the amount of acid
__ the amount should be the same on both sides of the equation

let x="gallons of 4%" __ x(4%)+20(10%)=(20+x)(5%) __ multiplying by 100 clears the percents

4x+200=100+5x __ 100=x
RELATED QUESTIONS
please show me the way you solve this problem. i am almost there. How many gallons of 5%... (answered by lwsshak3,josmiceli,KMST)

How many gallons of 5% acid solution should be mixed with 20 gallons of a 10% acid... (answered by stanbon)

How many gallons of a 4% acid solution should be mixed with 20 gallons of a 10% acid... (answered by scott8148)

How many gallons of a 4% acid solution should be mixed with 20 gallons of a 10% acid... (answered by stanbon)

How many gallons of 5% acid solution should be mixed with 20 gallons of a 10% acid... (answered by lwsshak3)

please help, this stuff makes no sense to me. How many liters each of a 12% acid... (answered by josmiceli,KMST)

please help with this problem a 10% acid solution is to be mixed with a 50% acid solution (answered by oberobic,richwmiller)

How many gallons fo a 20% acid solution should be mixed with a 30% acid solution to... (answered by ewatrrr,richwmiller)

How many gallons of a 4% acid solution should be mixed with 30 gallons of a 13% acid... (answered by checkley77,josmiceli,stanbon)