1.89 - .3x + 1x = 3.15

Question

The radiator in Natalie's car contains 6.3 L of antifreeze and water. This mixture is 30% antifreeze. How much of this mixture should she drain and replace with pure antifreeze so that there will be a mixtuure of 50% antifreeze?

Answer 1

1.89 -0.3x+1x=3.15

0.7x=3.15 -1.89=1.26

x=1.26/0.7

x=1.8