Boyle's Law provides a relation between the pressure and volume of a sample of gas at constant temperature. If the initial pressure and volume are `P_1` and `V_1` , and the final pressure and volume are `P_2` and `V_2` respectively, Boyle's Law states that `P_1*V_1 = P_2*V_2`
The sample of carbon monoxide initially occupies 3.2 l at 125 C. Let the pressure be `P_1` . If the gas is compressed, the pressure is increased. Let the final pressure be `P_2` . The volume now decreases to `V_2 = 25*(P_1/P_2)`
As the initial and final pressure of the gas is not specified it is not possible to determine `V_2` . For that, replace `P_1` and `P_2` in the formula `V_2 = 25*(P_1/P_2)` with the appropriate values.