How many quarts of pure antifreeze must be added to 2 quarts of a 10​% antifreeze solution to obtain a 20​% antifreeze​ solution?

Question

I need help with my math homework because it is hard. 

Answer 1

0.10(2) + 1.00x = 0.20(2 + x)

 

Can you solve for x and answer?

Answer 2

Set this up as a weighted combination of the mixtures.

 

x = quarts of 100% antifreeze

 

You have 2 quarts of 10% antifreeze.

 

(100%)x + (10%)(2) = (20%)(x + 2)

 

100x + 20 = 20(x + 2)

 

Solve for x.

 

5x + 1 = x + 2

 

4x = 1

 

x = 1/4 = 0.25 quarts of 100% antifreeze