There is one set of twins and one set of triplets. One twin is 7 years older than one triplet. If their combined ages are 44, how old is one of the twins?
Let T = age of triplet.
Twin's age = T + 
<gadget id="calculator">+7</gadget>
<output>7</output>
7.
Twin's combined age = 2 * (T + 7)
Triplet's combined age = 
<gadget id="calculator">3</gadget>
<output>3</output>
3T
2 * (T + 7) + 3T = 44
2T + 14 + 3T = 44
5T + 14 = 44
5T = 30.
T = 
<gadget id="calculator">6</gadget>
<output>6</output>
6.
Twin = 6 + 7 = 
<gadget id="calculator">6+7</gadget>
<output>13</output>
13.
The twins are each 
<gadget id="calculator">13</gadget>
<output>13</output>
13 years old.

<result>13</result>