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The cost of using a telephone in a hotel meeting room is $0.20 per minute. Which...


Question

The cost of using a telephone in a hotel meeting room is $0.20 per minute. Which of the following equations represents the total cost c, in dollars, for h hours of phone use?

Options

A)
c = 0.20(60h)
B)
c = 0.20h + 60
C)
c = \(\frac{60h}{0.20}\)
D)
c = \(\frac{0.20h}{60}\)

The correct answer is A.

Explanation:

Choice A is correct. The hotel charges $0.20 per minute to use the meeting-room phone. This per-minute rate can be converted to the hourly rate using the conversion 1 hour = 60 minutes, as shown below.

\(\frac{0.20}{minute}\) . \(\frac{60 minutes}{1 hour}\) = \(\frac{$(0.20 * 60)}{hour}\)

Thus, the hotel charges $(0.20 × 60) per hour to use the meeting room phone. Therefore, the cost F, in dollars, for h hours of use is c = (0.20 × 60)h, which is equivalent to c = 0.20(60h).

Choice B is incorrect because in this expression the per-minute rate is multiplied by h, the number of hours of phone use. Furthermore, the equation indicates that there is a flat fee of $60 in addition to the per-minute or per-hour rate. This is not the case. Choice C is incorrect because the expression indicates that the hotel charges $\((\frac{60}{0.20})\) per hour for the use of the meeting-room phone, not $0.20(60) per hour. Choice D is incorrect because the expression indicates that the hourly rate is \(\frac{1}{6}\) times the per-minute rate, not 60 times the per-minute rate.


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