12.00 liters of oxygen gas is under a pressure of 20 mm Hg. If the volume of this gas is decreased to 2.00 liters at constant temperature, what will the new pressure be?

Question

I believe this is Boyle's law and the answer should be 120 mm Hg, but according the answer on practice test it is saying 15 mm Hg.. Please verify. Thanks

Answer 1

12.00L x 20 mm = 2.00L x ?mm
?mm = 12.00 x 20/2 = 120 mm.
The key must be wrong.