There are four people A, B, C, and D. The weight of A is 7 kg heavier than that of B. The average weight of A and B is 1 kg more than the average weight of A, B, and D. The average weight of B, C, and D is 40.5 kg. The average weight of B and C is 41 kg. Ask: Who weighs the heaviest and how many kilograms does it weigh?
A、B、C、D四人，A的体重比B重7千克，A、B的平均体重比A、B、D的平均体重多1千克，B、C、D的平均体重是40.5千克，B、C的平均体重是41千克．试问：谁的体重最重，重多少千克？
<gadget id="calculator">40.5 * 3</gadget>
<output>121.5</output>

<gadget id="calculator">41 * 2</gadget>
<output>82</output>

<gadget id="calculator">121.5 - 82</gadget>
<output>39.5</output>

<gadget id="calculator">39.5 / 3</gadget>
<output>13.166667</output>

<gadget id="calculator">13.166667 + 1</gadget>
<output>14.166667</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">14.166667 / (1/6)</gadget>
<output>85.000002</output>

<gadget id="calculator">85.000002 - 7</gadget>
<output>78.000002</output>

<gadget id="calculator">78.000002 / 2</gadget>
<output>39.000001</output>

<gadget id="calculator">39.000001 + 7</gadget>
<output>46.000001</output>

<result>46.000001</result>