Try solving for the variable and get everything to one side
To Find :
How many gallons of a 80% antifreeze solution must be mixed with 100 gallons of 20% antifreeze to get a mixture that is 70% antifreeze.
Solution :
Let, x gallons of 80% antifreeze solution is required :
So,

Therefore, 500 gallons of 80% antifreeze solution is required.
Take the minise out the ecation so we can
If you are using a calculator, simply enter 16÷72×100 which will give you 22.22 as the answer.