Question

The tables below show running hours of three printers that produce greeting cards and the total number of greeting cards produced over three weeks. Number of Hours Machine Is Running Printer A Printer B Printer C Week 1 40 50 45 Week 2 45 50 40 Week3 55 30 6 Total Cards Produced Week 1 7,950 Week 2 7,800 Week 3 9,600 Printer B uses $15 in ink every hour. What is the ink cost for each card coming from printer B? A. $0.30 B. $0.50 C. $1.00 D. $1.50

Answer 1

is B correct?

Explanation:

Answer 2

B. $0.50

Explanation:

Assuming Printer C runs 60 hours (not 6) in Week 3, the equations for the number of cards per hour produced by each of the printers are ...

• 40a +50b +45c = 7950
• 45a +50b +40c = 7800
• 55a +30b +60c = 9600

The solutions to these equations can be found by various means. A graphing calculator (or any of several web sites) can solve the matrix equation to tell you the card production rates (in cards per hour) of each of the printers are ...

• a = 60
• b = 30
• c = 90

So the question about ink cost can be answered for printer B:

... ($15/hour)/(30 cards/hour) = (15/30) $/card = $0.50/card