John is twice as old as Mary and half as old as Tonya. If Tanya is 60, what is their average age?
John is 30 because 60 / 2 = 
<gadget id="calculator">60/2</gadget>
<output>30</output>
30.
Mary is fifteen because 30 / 2 = 
<gadget id="calculator">30/2</gadget>
<output>15</output>
15.
Their total age is 105 because 60 + 30 + 15 = 
<gadget id="calculator">60+30+15</gadget>
<output>105</output>
105.
Their average age is 35 because 105 / 3 = 
<gadget id="calculator">105/3</gadget>
<output>35</output>
35.

<result>35</result>