Answer: 7 atm
Step-by-step explanation:
According to Dalton's Law, the total pressure is the sum of all the individual gas pressures
Hence, Ptotal = P1 + P2 + P3
Since, Gas A = 2 atm
Gas B = 1 atm
Gas B = 4 atm
Ptotal = (2 + 1 + 4) atm
Ptotal= 7 atm
Thus, the total pressure of the gas mixture is 7 atmosphere.