Test tommorow, please help with this one ques, its easy for most!!!?

Question

How much of a 40% antifreeze solution must a mechanic mix with a 70% antifreeze solution if he needs 31 gallons of a 50% antifreeze solution?

- i kno its easy i just forget the process, thanks

Answer 1

Let x denote the number of gallons of 40% antifreeze solution
Let y denote the number of gallons of 70% antifreeze solution

Then x gallons of 40% antifreeze solution contains 0.4x gallons of antifreeze, y gallons of 70% antifreeze solution contains 0.7y gallons of antifreeze, and 31 gallons of 50% antifreeze solution contains 31*0.5 gallons of antifreeze.

So

x + y = 31
0.4x + 0.7y = 15.5

Solve for x and y.

Answer 2

You idiot. Do your own homework. You're just going to be a mechanic. It's not like you're in REAL college, just a school for boneheads like you.