i need help: i have 10 gallons at a 5% solution, i need to

[walter001]

i have 10 gallons at a 5% solution, i need to add x gallons at 20 % solution and end up with a solution of 6%. How do i set up this formula? thanks

 

[galactus]

You have a 5% mixture, so it's not going to take much of a 20% to bring it up to 6%.

You have 10 gallon at 5% concentration: 0.05(10)

You have x gallons at 20% concentration: 0.20x

They must equal 6% concentration: 0.05(10)+0.20x=0.06(x+10)

Solve for x.

 

[Denis]

  a  @ x
  b  @ y
========
 a+b @ z

(ax + by) / (a + b) = z

Tatoo that on your wrist :wink: