The sum of A and B is 451. The ratio of A to B is 4:7. What is B?
甲、乙两数的和是451，甲数与乙数的比是4：7，乙数是多少．
<gadget id="calculator">4 + 7</gadget>
<output>11</output>

<gadget id="calculator">7 / 11</gadget>
<output>7/11 = around 0.636364</output>

<gadget id="calculator">451 * (7/11)</gadget>
<output>287</output>

<result>287</result>