BSAS 2012 Level 2 CFA exam QUESTION 47 AM SESSION people, solution, 2012, mortgage, into

Beatnik

Any of you fine people have any comments on this:  
In Q47, the BSAS solution calculated the CPR for a mortgage that is 48 months into a 60 month term under 175 PSA as:
CPR = (24/30)*6.0%*1.75
I’m all good with this except for this 24/30 factor, where the hell did this come from?
Cheers
N

jbaldyga

I’m cracked…sorry guys, I don’t know why I thought it was 48 of 60 months….this was the last question I did before quitting yesterday, in the cold light of morning I see clearly.
Thanks and good luck.
N