There are 3 books on Mathematics, 4 on Physics and 5 on English. How many different collections can be made such that each collection consists of:
Number of book of mathematics=3
Number of book of physics=4
Number of book of English=5
a.One book of each subject=
b.At least one book of each subject=
c. Adding one book of English=
So, a-(ii), b-(iii), c-(i)