Bunuel wrote:
Joe’s pie shop serves only chocolate pies and coconut cream pies. On a given day, Joe sold 200 pies, with each customer buying either one coconut cream pie, one chocolate pie, or one of each. If 80 customers bought both a coconut cream and a chocolate pie, how many chocolate pies did Joe sell?
(1) 40 customers did not buy a chocolate pie.
(2) 120 customers bought a coconut cream pie.
2 overlapping sets can always be broken into the same 4 categories (both, only A, only B, neither).
This is a Precise approach.
total number of pies= 200
(both chocolate and cocount) = 80
neither = 0 as all customers bought at least one pie
so (only chocolate) + (only cococunt) = total - (both) - (neither) = 200 - 80 - 0 = 120
question - how much is (only chocolate) + (both chocolate and coconut)?
Since we know that (only chocolate) + (only coconut) = 120, all we need to is the value of (only coconut).
(1) then these 40 must have bought a cococunt pie meaning that (only coconut) = 40. Exactly what we need!
Sufficient.
(2) gives us (only coconut) + (both). Since we know that (both) = 80, we can calculate (only coconut).
Sufficient.
(D) is our answer.
_________________
David
Senior tutor at examPAL
Signup for a free GMAT course
We won some awards:
Save up to $250 on examPAL packages (special for GMAT Club members)
close
71% (01:41) correct 
