Question

A 30% solution of fertilizer is to be mixed with a 70% solution of fertilizer in order to get 160 gallons of a 60% solution. How many gallons of the 30% solution and 70% solution should be mixed?

Answer 1

We will determine the number of gallons of the 30% & 70% solutions as follows:

$0.30x+0.70(160-x)=0.60\cdot100\Rightarrow0.30x+112-0.70x=60$$\Rightarrow-0.4x+112=60\Rightarrow-0.4x=-52$$\Rightarrow x=130$

So, we would need 130 gallons of 30% solution, and:

$160-(130)=30$

And we would also need 30 gallons of 70% solution.