Xiao Ming went to a bicycle factory to work and study during the summer vacation. He agreed to work for 7 weeks. The boss gave him a bicycle plus 200 yuan as remuneration. Later, because he only worked for 4 weeks, the boss gave him a bicycle plus 20 yuan. What is the value of a bicycle in dollars.
小明利用暑假到一家自行车厂勤工俭学，讲好了干7个星期，老板给他一辆自行车外加200元作报酬，后因他只做了4个星期，老板给了他一辆自行车外加20元钱的报酬，则一辆自行车的价值是多少元．
<gadget id="calculator">200 / 49</gadget>
<output>200/49 = around 4.081633</output>

<gadget id="calculator">20 / 28</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(200/49) - (5/7)</gadget>
<output>165/49 = around 3.367347</output>

<gadget id="calculator">1 / 28</gadget>
<output>1/28 = around 0.035714</output>

<gadget id="calculator">1 / 49</gadget>
<output>1/49 = around 0.020408</output>

<gadget id="calculator">(1/28) - (1/49)</gadget>
<output>3/196 = around 0.015306</output>

<gadget id="calculator">(165/49) / (3/196)</gadget>
<output>220</output>

<result>220</result>