The sum of the three numbers is 120, the number A is 3 times the number B, and the number C is 15 more than the number B, what is the number C?
三数之和是120，甲数是乙数的3倍，丙数比乙数多15，丙数是多少．
<gadget id="calculator">120 - 15</gadget>
<output>105</output>

<gadget id="calculator">3 + 1 + 1</gadget>
<output>5</output>

<gadget id="calculator">105 / 5</gadget>
<output>21</output>

<gadget id="calculator">21 + 15</gadget>
<output>36</output>

<result>36</result>