John raises butterflies.  He has 4 jars of 10 caterpillars each.  40% of them fail to become butterflies, but the rest become caterpillars.    He sells the butterflies for $3 each.  How much money does he make?
He has 4*10=
<gadget id="calculator">4*10</gadget>
<output>40</output>
40 caterpillars.
40*.4=
<gadget id="calculator">40*.4</gadget>
<output>16</output>
16 fail to form.
That means he has 40-16=
<gadget id="calculator">40-16</gadget>
<output>24</output>
24 butterflies.
So he makes 24*3=$
<gadget id="calculator">24*3</gadget>
<output>72</output>
72.

<result>72</result>