A student is selecting 5 different geography books, 4 different chemistry books, and one of 7 different science books. In how many different ways can a student select them?

There would be 5184 ways in which each subject books can be selected.

Explanation:

Number of geography books = 5

Number of chemistry books = 4

Number of Science books = 7

Different ways of selecting geography books = 5!

= 5 X 4 X 3 X 2 X 1

= 120

Different ways of selecting chemistry books = 4!

= 4 X 3 X 2 X 1

= 24

Different ways of selecting Science books = 7!

= 7 X 6 X 5 X 4 X 3 X 2 X 1

= 5040

Total different possible ways they can select them = 120 + 24 + 5040

= 5184