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 = 
<gadget id="calculator">10*2/5</gadget>
<output>4</output>
4 books for $2.50 each.
She will sell 10 - 4 = 
<gadget id="calculator">10-4</gadget>
<output>6</output>
6 books for $2 each.
Her earnings for the 4 books at $2.50 will be $2.50 x 4 = $
<gadget id="calculator">2.5*4</gadget>
<output>10</output>
10.
Her earnings for the 6 books for $2 each will be $2 x 6 = $
<gadget id="calculator">2*6</gadget>
<output>12</output>
12.
Thus, Lovely's total earning if all 10 books are sold is $10 + $12 = $22.

<result>22</result>