Have a calculation question...

How many liters of 2% brind solution must be added to 30 liters of 10% brind solution to dilute it to a 8% solution.

Do not just want the answer, would like formula to solve...

x=amount of 2% solution.

0.02x+0.10(30)=0.08(\underbrace{30+x}_{\text{added to 30}})

Solve for x.