According to the given information, the total cost c, in dollars, for h hours of phone use is c=(0.20 × 60)h.
For usage of the conference room phone, the hotel charges $0.20 per minute.
The conversion 1 hour = 60 minutes can be used to convert this per-minute rate to an hourly rate as demonstrated in the following equation.
[tex]\frac{0.20}{minute}[/tex] × [tex]\frac{60 minutes}{1 hour}[/tex] = [tex]\frac{0.20 * 60}{hour}[/tex]
The cost to use the conference room phone is therefore $0.20 per hour at the hotel.
As a result, c=(0.20 × 60)h, or c=0.20, is the cost c in dollars for h hours of use (60h).
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