Xiaohong spent 15 yuan on books last month, accounting for 20% of the total expenditure. How much did Xiaohong spend in total last month?
小红上个月买书花了15元，占总支出的20%，小红上个月一共花了多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / (1/5)</gadget>
<output>75</output>

<result>75</result>