A building has 10 floors. It takes 15 seconds to go up the stairs to the even-numbered floors and 9 seconds to go up to the odd-numbered floors.  This includes getting to the first floor. How many minutes does it take to get to the 10th floor?
So for all even-numbered floors (2, 4, 6, 8, 10), it takes 5*15= 
<gadget id="calculator">5*15</gadget>
<output>75</output>
75 seconds.
And for all odd-numbered floors (1, 3, 5, 7, 9) it takes 5*9= 
<gadget id="calculator">5*9</gadget>
<output>45</output>
45 seconds.
To climb all the floors, it takes 75+45= 
<gadget id="calculator">75+45</gadget>
<output>120</output>
120 seconds.
So it takes 120/60=
<gadget id="calculator">120/60</gadget>
<output>2</output>
2 minutes to get to the 10th floor.

<result>2</result>