Zhang Hua reads a storybook, and on the first day he read the whole book (15/100) 4 pages less. At this time, the ratio of the number of pages he has read to the number of remaining pages is 1:7. How many pages are there in this storybook? Page?
张华看一本故事书，第一天看了全书的(15/100)少4页，这时已看的页数与剩下的页数的比是1：7，这本故事书有多少页？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 + 7</gadget>
<output>8</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(3/20) - (1/8)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">4 / (1/40)</gadget>
<output>160</output>

<result>160</result>