The cost for burning a 75-watt bulb is given by the function c ( h ) = 0.0045 h , where h represents the number of hours that the bulb burns. How much does it cost to burn a 75-watt bulb for 3 hours per night for a 31-day month? Express your answer to the nearest cent.
A) $0.50
B) $0.42
C) $0.33

Question

Quizplus · Accepted Answer

The bulb burns for 3 hours per night, so it burns for a total of 3 x 31 = 93 hours in the month. 
Using the given function, we can calculate the total cost: 
c(h) = 0.0045h 
c(93) = 0.0045(93) = 0.4185 
Rounding to the nearest cent, the cost is $0.42. 
Therefore, the best choice is B.

The Cost for Burning a 75-Watt Bulb Is Given by the Function