Answer:
7 Liters is the new volume
Step-by-step explanation:
For this problem, we assume that T° keeps on constant. Therefore we can apply Boile Mariotte's concept: pressure can be modified in a proportional indirectly way to volume
V₁ . P₁ = P₂ . V₂
12.5 L . 42 mmHg = 75 mmHg . V₂
(12.5 L . 42 mmHg) / 75 mmHg = V₂
7L = V₂
As the pressure has increased, the volume decreased.