Boyle’s law states that for a given mass of gas, that the volume is inversely proportional to its pressure provided the temperature is constant.

V ∝ 1/P

K = PV

ie. V = K/P

P_{1}V_{1} = P_{2}Vsub>2

**Example**:

A given mass of gas of pressure 120 N/M2 occupies a volume of 30cm3. What will be the pressure exerted when the volume rises to 90cm3.

**Solution:**

P_{1}V_{1} = P_{2}Vsub>2

P_{1} = 120N/M2, V1 = 30cm3, P2 =? V2 = 90cm3

∴ P_{2} = (P1 V1)/V = (120 x 30)/90

= 40N/M2