As Dan is learning to screen-print t-shirts to sell at the craft fair, he makes t-shirts, over the first hour, at the rate of one every 12 minutes. Then, in the second hour, he makes one at the rate of every 6 minutes. How many t-shirts does he make over the course of those two hours?
He made 60/12=
<gadget id="calculator">60/12</gadget>
<output>5</output>
5 the first hour.
He made 60/6=
<gadget id="calculator">60/6</gadget>
<output>10</output>
10 the second hour.
He made 5+10=
<gadget id="calculator">5+10</gadget>
<output>15</output>
15.

<result>15</result>