The best definition for the term substitution would be...
the action of replacing someone or something with another person or thing.
ANSWER = 17.5% of 360 = 63
EXPLANATION:
Find 10% of 360 = 36
Then 5% of 360 = 18
Then 2.5% of 360 = 9
Add them together
so 17.5% of 360 = 63
20 is permutation
22 is counting principle
Hope it help.