In an examination , part A was attempted by 60 students , part B by 52 students and part C by 45 students . 22 students attempted both parts A and B , 12 attempted both parts B and C , 20 attempted parts A and C and 4 attempted all three parts .

(a) How many students attempted part A but not parts B and C ?

(b) How many students attempted part Bbut not parts A and C ?

(c) How many students attempted at least 2 parts ?

For (A) , n(A-(B n C))=60-12=48 but it is wrong .

i tried the same method on B and i hv no idea at all for c .

THanks .