The pressures given are the partical pressures of the two gases.
The law of Dalton or of the partial pressures states that the total pressure of a mixture of gases is equal to the sum of the pressures of all the gases.
So, in this case:
Total pressure = pressure of nitrogen + pressure of carbon dioxyde.
Of course both terms must be in the same units.
i have found that the pressures for this problem are:
Pressure of nitrogen = 984 torr
Pressure of carbon dioxyde = 345 torr
Total pressure = 984 torr + 345 torr = 1329 torr.
Now convert to atm: 1 atm = 760 torr
=> 1329 torr * 1 atm / 760 torr = 1.74868 atm ≈ 1.75 atm
Answer: 1.75 atm