A story book costs 4 yuan. If Xiao Ming buys this story book, then the money ratio between Xiao Ming and Xiao Qiang is 2:3; if Xiao Qiang buys this story book, then the money ratio between the two is 4:5, how much money did Xiao Ming originally have money?
一本故事书售价4元．如果小明买了这本故事书，那么小明与小强的钱数之比是2：3；如果小强买了这本故事书，那么两人的钱数之比是4：5，小明原来有多少元钱？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">2 / 5 / (4/9)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">4 / (1/10)</gadget>
<output>40</output>

<result>40</result>