word problem: how many liters must be mixed to obtain....

Please help me out I am having a hard time figuring out where to even begin with this problem How many liters of a 10% alcohol must be mixed with 12 liters of a 20% alcohol solution to obtain a 14% alcohol solution? Thanks for your help.

Use the standard "mixture" set-up:

. . . .liters solution:
. . . . .10%: x
. . . . .20%: 12
. . . . .mix: 12 + x

. . . .percent alcohol:
. . . . .10%: 0.1
. . . . .20%: 0.2
. . . . .mix: 0.14

. . . .liters alcohol:
. . . . .10%: 0.1x
. . . . .20%: 0.2(12) = ??
. . . . .mix: ??

Complete the table. Add the input amounts of alcohol; set equal to the output amount. Solve for the variable.

Eliz.