To make a call from a payphone, you must pay $0.25 for each minute of your call. After 16 minutes, that price drops to $0.2 per minute. How much would a 36-minute call cost?
First 16 minutes would be a cost of 16 * 0.25 = $
<gadget id="calculator">16*0.25</gadget>
<output>4</output>
4.
After that, there are 36 - 16 = 
<gadget id="calculator">36-16</gadget>
<output>20</output>
20 minutes of the call left.
And these 20 minutes cost 20 * 0.2 = $
<gadget id="calculator">20*0.2</gadget>
<output>4</output>
4.
So in total, the 36-minute call would cost 4 + 4 = $8.

<result>8</result>