The beverage in bucket A is 4 times that of bucket B. If 15 kg is taken out from bucket A and poured into bucket B, then the weight of the two buckets of beverage is equal. How much is the original beverage in bucket A?
甲桶的饮料是乙桶的4倍，如果从甲桶取出15千克倒入乙桶，那么两桶饮料的重量相等，甲桶原有饮料多少千克？
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

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

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

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

<result>40</result>