A worker is divided into three periods of morning, middle and evening to complete a job. The ratio of the workload of the three periods is 1:2:3. It is known that the work efficiency of his morning shift is 3 per hour, and the time spent accounts for 2% of the total time. (4/15), if the total number of jobs is 50, how long does he work in the middle shift and evening shift?
一个工人分为早、中、晚三段时间完成一项工作，三段工作量的比是1：2：3，已知他早班的工作效率是每小时3个，所用时间占总时间的(4/15)，如果工作总量是50个，他中班和晚班一共工作多长时间？
<gadget id="calculator">1 + 2 + 3</gadget>
<output>6</output>

<gadget id="calculator">50 / 6</gadget>
<output>25/3 = around 8.333333</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1 / 3 / (4/15)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">1 - (4/15)</gadget>
<output>11/15 = around 0.733333</output>

<gadget id="calculator">(25/3) * (5/4) * (11/15)</gadget>
<output>275/36 = around 7.638889</output>

<result>275/36 = around 7.638889</result>