The ratio of the number of people in the first grade to the second grade is 5:7, and the ratio of the number of people in the second grade to the third grade is 14:15. It is known that the third grade has 10 more people than the second grade, so how many people are there in the first grade?
一年级与二年级的人数的比是5：7，二年级与三年级人数比是14：15，已知三年级比二年级多10人，那么一年级有多少人？
<gadget id="calculator">15 - 14</gadget>
<output>1</output>

<gadget id="calculator">10 / 1</gadget>
<output>10</output>

<gadget id="calculator">14 / 7</gadget>
<output>2</output>

<gadget id="calculator">10 * 2 * 5</gadget>
<output>100</output>

<result>100</result>