The ages of A, B, C and D are compared. A’s age is the sum of the ages of the other three (1/2), B’s age is the sum of the ages of the other three (1/4), and C is the sum of the ages of the other three (1/5) ), Ding is 45 years old. Do you know how old is A?
甲乙丙丁四个人比年龄，甲的年龄是另外三人年龄和的(1/2)，乙的年龄是另外三人年龄和(1/4)，丙是另外三人年龄和的(1/5)，丁是45岁．你知道甲多少岁吗？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

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

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/3) - (1/5) - (1/6)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">45 / (3/10)</gadget>
<output>150</output>

<gadget id="calculator">150 * (1/3)</gadget>
<output>50</output>

<result>50</result>