The box office revenue of a children's paradise during the "May 1st" Golden Week was 90,000 yuan, which was 20% more than the box office revenue of the whole month of April. How much is the box office revenue in April?
某儿童乐园在"五一"黄金周期间的票房收入为9万元，比四月份全月的票房收入还多20%，四月份的票房收入是多少万元．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">9 / (6/5)</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>