The ratio of number A to number B is 5:3. It is known that the sum of numbers A and B is 24. What is the number A?
甲数和乙数的比是5：3，已知甲、乙两数的和是24，则甲数是多少．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">24 / 8</gadget>
<output>3</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>