Answer is 1.117 atm.
Explanation;
Partial pressure of a gas is the pressure of the gas on the container when the gas is alone.
Here, there are 3 gases as methane, chlorine and carbon monoxide .
Partial pressures are given as
methane - 0.215 atm
chlorine - 0.066 atm
carbon monoxide - 0.836 atm
Total pressure is the pressure on the container which is due to the whole mixture of gases.
Total pressure = sum of the pressure of each gas
= 0.215 atm + 0.066 atm + 0.836 atm
= 1.117 atm
