thirty gallons of a %20 acid solution is needed for an experiment. only %40 and %10 acid solution much of each should be mixed to form the needed solution

Question

this a  college math word problem. please help solve

Answer 1

What we don't know is how much of each individual solution (the 40% and 10% acid solutions) must be mixed to form the 30 gal of 20% acid. If we let x = the amount of 40% acid, then the amount of 10% acid needed is 30 - x. Thus, we can form the following equation:

 

.40x + .10(30 - x) = .20(30)

 

You can multiply both sides of the equation by 100 to clear the decimals.

 

40x + 10(30 - x) = 20(30)

 

You should now be able to solve this linear equation for x, Bonnie.