The number of boys in the school chorus is equivalent to 60% of the girls. If (1/3) of the girls are replaced by boys, then there are 28 boys. How many boys are there in the chorus?
学校合唱队中男生人数相当于女生的60%，如果将(1/3)的女生换成男生，这时男生有28人，合唱队原有男生多少人？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 * (1/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(3/5) + (1/3)</gadget>
<output>14/15 = around 0.933333</output>

<gadget id="calculator">28 / (14/15)</gadget>
<output>30</output>

<gadget id="calculator">30 * (3/5)</gadget>
<output>18</output>

<result>18</result>