Since all the answers are in litres, it would be smart to convert what we have to litres as well.
Since there are 1000mL in a L, we divide our mL by 1000 to get L.
120 / 1000 = 0.120 L
Since there are 18 of these, multiply by 18.
0.120 x 18 = 2.16
Answer is 2.16 L