How old would a Macbook Pro need to be in order to have a non-64bit Intel processor? My friend has a MBP that was bought 2 or 3 years ago, and I need to help him prepare some software to run. What are the chances he won't be able to boot from a 64bit Linux live USB flash drive?
I'd recommend he check rather than assume based on age. Here are directions on How to tell if your Intel-based Mac has a 32-bit or 64-bit processor

http://support.apple.com/kb/HT3696