How long does it take to cook a 7.5 pound whole chicken

20 minutes per pound at 350. Internal temp should reach 165 before eating.

Edit. If you let it rest after cooking the internal temp will go up. :)

JustDahlia, that seems kind of long. The instructions that come with the Reynolds Bags call for 1.5 hours at 350 for a 7 lb chicken. Your method calls for 2.5 hours. Another hour for just a half lb. more seems like a lot.

Can I put 2 three pound turkey breasts in one cooking bag? If so, for how long do I bake them?

I wouldn't put both of them in one bag. Reynolds makes smaller sized bags for poultry of less than 7 lbs. I would use 2 of the smaller bags and follow the instructions included in the package.