For a book, Xiaohong read 25 pages a day for the first 6 days, 40 pages a day after that, and just finished reading it in 4 days. How many pages do she read on average every day?
一本书，小红前6天每天读25页，以后每天读40页，又经过4天正好读完，平均每天读多少页？
<gadget id="calculator">25 * 6</gadget>
<output>150</output>

<gadget id="calculator">40 * 4</gadget>
<output>160</output>

<gadget id="calculator">150 + 160</gadget>
<output>310</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">310 / 10</gadget>
<output>31</output>

<result>31</result>