The first store charges $3 for 6 apples while the second store charges $4 for 10 apples. How many cents can you save on each apple from buying $4 for 10 apples than from $3 for 6 apples?
In the first store, each apple costs $3/6 = $
<gadget id="calculator">3/6</gadget>
<output>1/2 = around 0.5</output>
0.5.
In the second store, each apple costs $4/10 = $
<gadget id="calculator">4/10</gadget>
<output>2/5 = around 0.4</output>
0.4.
So, you can save $0.5 - $0.4 = $0.1 on each apple from buying $4 for 10 apples than from $3 for 6 apples.
In cents, this is equal to $0.1 x 100 = 
<gadget id="calculator">0.1*100</gadget>
<output>10</output>
10.

<result>10</result>