Question

The gaseous product of a reaction is collected in a 64-L container at 27oC. The pressure in the container is 1.45 atm. How many moles of the gas are in the container?

Answer 1

since 1 mole occupies 22.4L at STP, and PV/nT is constant, you want n such that
1.45*64/((27+273)n) = 1*22.4/(273n)

Answer 2

I would use PV = nRT and
n = PV/RT = 1.45*64/0.08205*(273+27)
Looks simpler to me.