In order to survive the winter, the little white rabbit and the little black rabbit both stored some carrots. It is known that the amount of carrots stored by the little white rabbit is three times that of the little black rabbit. After they each ate 5 carrots, the number of carrots left by the little white rabbit was 4 times that of the little black rabbit. So how many carrots do they have left?
为了过冬，小白兔和小黑兔都储藏了一些胡萝卜．已知小白兔储藏的胡萝卜数量是小黑兔储藏数量的3倍．它们各吃了5个胡萝卜后，小白兔剩下的胡萝卜数量是小黑兔剩下数量的4倍．那么它们剩下的胡萝卜共有多少个．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 - 5</gadget>
<output>10</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

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

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<gadget id="calculator">10 + 40</gadget>
<output>50</output>

<result>50</result>