Two identical containers are adjacent to each other. They both have Volume =4 L

Two identical containers are adjacent to each other. They both have Volume =4 L and Pressure = 1.5atm. One contains O2, a diatomic gas, (molar mass 32g/mol) at initial temperature 250K. The other contains argon, a monoatomic gas, (molar mass 40g/mol) at some unknown initial temperature T. After the boxes exchange heat (but not particles) they both reach a final temperature of 400K. Assume they both act as ideal gasses. How many moles of Oxygen and Argon gas are present?