David is buying 3 books in a trilogy set for $24.81. He will save $6.69 by buying the trilogy set instead of buying individual books. If each book costs the same amount, how much does each of the 3 books cost when purchased individually?

Cost of each individual book = $10.5

Step-by-step explanation:

Given:

Cost of 3 book set = $24.81

Amount save = $6.69

Find:

Cost of each individual book

Computation:

Assume:

Cost of each individual book = a

Total cost = 3a

So,

Total cost = $24.81 + $6.69

Total cost = $31.5

So,

3a = $31.5

a = $10.5

Cost of each individual book = $10.5