A farmer is selling ducks and chickens at the market. He sells ducks for $10 and chickens for $8. He sells 5 chickens and some ducks. He then spends half his earnings on a new wheelbarrow. After buying it, someone sees it and agrees to pay the farmer double what the farmer paid and the farmer earns another $60. How many ducks did the farmer sell?
The wheelbarrow cost $30 because 60 / 2 = 
<gadget id="calculator">60/2</gadget>
<output>30</output>
30.
The farmer earned $60 from selling fowl because 30 / (1/2) = 
<gadget id="calculator">30/(1/2)</gadget>
<output>60</output>
60.
The farmer earned $40 selling chickens because 5 x 8 = 
<gadget id="calculator">5*8</gadget>
<output>40</output>
40.
The farmer earned $20 selling ducks because 60 - 40 = 
<gadget id="calculator">60-40</gadget>
<output>20</output>
20.
The farmer sold 2 ducks because 20 / 10 = 
<gadget id="calculator">20/10</gadget>
<output>2</output>
2.

<result>2</result>