The answer is 12.8 cm³
The volume ( v) of a gas in a container at a constant temperature varies inversely as the pressure (p):
v = k/p
p * v = k (k - constant)
p1v1 = k
p2v2 = k
So, p1v1 = p2v2
v1 = 24 cm³
p1 = 16 lb
v2 = ?
p2 = 30 lb
24 * 16 = x * 30
384 = x * 30
x = 384 / 30
x = 12.8 cm³