Cindy can run at 3 miles per hour and walk at 1 mile per hour. If she runs for half a mile and then walks for half a mile, how many minutes will it take her to travel the full mile?
It will take her 0.5 miles / 3 mph * (60 minutes / 1 hour) = 
<gadget id="calculator">0.5/3*60</gadget>
<output>10</output>
10 minutes to run half a mile.
It will take her 0.5 miles / 1 mph * (60 minutes / 1 hour) = 
<gadget id="calculator">0.5/1*60</gadget>
<output>30</output>
30 minutes to walk half a mile.
Her total time is 10 + 30 = 
<gadget id="calculator">10+30</gadget>
<output>40</output>
40 minutes.

<result>40</result>