A vendor at the market is selling sunglasses for $30 each. He has to spend a certain amount to buy these sunglasses. He sells 10 pairs in a day. He then takes half his profits and uses it to buy a new sign, which costs $20. How much does each pair of sunglasses cost him to buy?
His profits were $40 because 20 / .5 = 
<gadget id="calculator">20/.5</gadget>
<output>40</output>
40.
He made $300 selling sunglasses because 10 x 30 = 
<gadget id="calculator">10*30</gadget>
<output>300</output>
300.
His costs for the sunglasses were $260 because 300 - 40 = 
<gadget id="calculator">300-40</gadget>
<output>260</output>
260.
The sunglasses cost him $26 each because 260 / 10 = 
<gadget id="calculator">260/10</gadget>
<output>26</output>
26.

<result>26</result>