The number obtained after expanding a decimal to 3 times the original number is 7.2 larger than the original number. What is the original number.
将一个小数扩大到原数的3倍后得到的数比原数大7.2．原数是多少．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">7.2 / 2</gadget>
<output>3.6</output>

<result>3.6</result>