Answer : C) 12.8 cubic cm
The volume ( v) of a gas in a container at a constant temperature varies inversely as the pressure (p)
If y is inversely proportional to x then

where k is constant of proportionality
v is inversely proportional to p then

the volume of a gas is 24 cubic centimeters when the pressure is 16 pounds
Given : v= 24 and p = 16. We need to find out k

Multiply by 16 on both sides
k = 384
Now we find out the volume under a pressure of 30 pounds

= 12.8 cubic cm