Boys accounted for (7/12) of the fifth grade students in Hongxing Primary School, and 15 boys were transferred later, so that boys accounted for (3/5) of the total number of fifth grade students. How many people were there in the fifth grade?
红星小学五年级学生中男生占(7/12)，后来又转来15名男生，这样男生占五年级总人数的(3/5)．五年级原有多少人？
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<gadget id="calculator">7 / 5</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">(3/2) - (7/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">15 / (1/10)</gadget>
<output>150</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">1 - (7/12)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">150 / (5/12)</gadget>
<output>360</output>

<result>360</result>