The school bought 25 footballs, which is 5 less than twice the number of basketballs. How many basketballs did the school buy?
学校买来足球25个，比篮球个数的2倍少5个，学校买来篮球多少个．
<gadget id="calculator">25 + 5</gadget>
<output>30</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<result>15</result>