Official Solution:Three copy machines are available for making copies of a document. Copier A can produce 12 copies per minute, Copier B can produce 7 copies per minute, and Copier C can produce 19 copies per minute. The cost of making a single copy with Copier A is 8 cents, with Copier B is 5 cents, and with Copier C is 11 cents. To use any of the copiers, an attendant must be hired and be paid a salary of $30 per hour, rounded up to the nearest hour. This means that if a copier is used for any portion of an hour, the attendant must be paid for the entire hour. If only one copier among Copier A, Copier B, and Copier C is used to make 1,200 copies of the document, what is the lowest total cost taking into account both the cost per copy and the attendant's salary? A. $90
B. $120
C. $125
D. $150
E. $156
We need to determine the lowest total cost to make 1,200 copies of the document, taking into account both the cost per copy and the attendant's salary, if only one copier among Copier A, Copier B, and Copier C is used.
To calculate the total cost of using each copier, we need to consider the time it takes to produce the copies and the attendant's salary:
Using Copier A: It takes 1,200 copies / 12 copies per minute = 100 minutes to produce the copies. Rounding up to the nearest hour, the attendant's salary is $30 x 2 hours = $60. The total cost is:
• Total cost = (1,200 copies x $0.08 per copy) + $60 = $156
Using Copier B: It takes 1,200 copies / 7 copies per minute ≈ 170 minutes to produce the copies. Rounding up to the nearest hour, the attendant's salary is $30 x 3 hours = $90. The total cost is:
• Total cost = (1,200 copies x $0.05 per copy) + $90 = $150
Using Copier C: It takes 1,200 copies / 19 copies per minute ≈ 63 minutes to produce the copies. Rounding up to the nearest hour, the attendant's salary is $30 x 2 hours = $60. The total cost is:
• Total cost = (1,200 copies x $0.11 per copy) + $60 = $192
Therefore, using Copier B would result in the lowest total cost of $150 to make 1,200 copies of the document, taking into account both the cost per copy and the attendant's salary.
Answer: D
_________________