Give the step-by-step reasoning process and then the final answer. A yearly book sale is held in school where students can sell their old books at a cheaper price. Two-fifths of Lovely's books can be sold for $2.50 each and the rest for $2 each. How much will Lovely earn if all 10 books were sold?
Lovely will sell 10 x 2 / 5 = 4 books for $2.50 each. She will sell 10 - 4 = 6 books for $2 each. Her earnings for the 4 books at $2.50 will be $2.50 x 4 = $10. Her earnings for the 6 books for $2 each will be $2 x 6 = $12. Thus, Lovely's total earning if all 10 books are sold is $10 + $12 = $22.
The final answer: 22.