The ratio of the number of volleyballs to footballs in the school sports room is 9:10, and the ratio of footballs to basketballs is 5:7. It is known that there are 69 basketballs and volleyballs. How much more are there basketballs than volleyballs?
学校体育室有排球与足球个数的比是9：10，足球与蓝球个数的比是5：7．已知蓝球与排球共有69个，蓝球比排球多多少？
<gadget id="calculator">9 + 14</gadget>
<output>23</output>

<gadget id="calculator">69 / 23</gadget>
<output>3</output>

<gadget id="calculator">3 * 14</gadget>
<output>42</output>

<gadget id="calculator">3 * 9</gadget>
<output>27</output>

<gadget id="calculator">42 - 27</gadget>
<output>15</output>

<result>15</result>