Ideal gas container problem

[chicagobears34]

Homework Statement

A container of gas at 3.90atm pressure and 136 ∘C is compressed at constant temperature until the volume is halved. It is then further compressed at constant pressure until the volume is halved again.
What is the final temperature of the gas?

Homework Equations

PV=nRT

The Attempt at a Solution

seems like a very easy question, but I'm doing Mastering Physics and it is saying I am wrong.
the volume is being halved and the pressure remains constant, so shouldn't the temperature just be halved also?
I got 68 degrees celsius as my answer, but Mastering Physics says it is wrong and I should check my signs but that shouldn't be an issue.

 

[collinsmark]

Don't forget to convert the temperature to an absolute scale (such as Kelvin) before you start the calculations. Then remember to convert it back to deg C when you're finished.

 

[chicagobears34]

thanks collinsmark! totally forgot about that :p