A shop buys a kind of diary, the purchase price is 1.60 yuan each, and the selling price is 0.9 yuan more than twice the purchase price, how many diaries need to be sold if the store wants to make 100 yuan Book?
某商店购进一种日记本，其中购进价格为每本1.60元，售出每本价格是购进价格的2倍还多0.9元，此商店要想赚100元，需要售出多少本日记本？
<gadget id="calculator">1.6 * 2</gadget>
<output>3.2</output>

<gadget id="calculator">0.9 - 1.6</gadget>
<output>-0.7</output>

<gadget id="calculator">3.2 + (-0.7)</gadget>
<output>2.5</output>

<gadget id="calculator">100 / 2.5</gadget>
<output>40</output>

<result>40</result>