Question

Difficulty: MediumSystems of Linear Equations

A commercial print shop operates two types of high-speed printers, Printer M and Printer N. Operating simultaneously for 55 hours, 22 units of Printer M and 33 units of Printer N print a total of 5,5005,500 pages. Operating simultaneously for 44 hours, 55 units of Printer M and 22 units of Printer N print a total of 6,6006,600 pages. What is the hourly page output of a single Printer M?

Answer: 250 pages per hour

Answer

The hourly page output of a single Printer M is 250 pages per hour.
Dividing each total page output by the corresponding number of hours produces the simplified linear system: 2m+3n=11002m + 3n = 1100 and 5m+2n=16505m + 2n = 1650, where mm and nn are the hourly rates of Printer M and Printer N. Multiplying the first equation by 22 gives 4m+6n=22004m + 6n = 2200, and multiplying the second equation by 33 gives 15m+6n=495015m + 6n = 4950. Subtracting the two equations eliminates nn, giving 11m=275011m = 2750, which simplifies to m=250m = 250 pages per hour.

Step-by-Step Solution

1
Define variables and write initial algebraic equations based on time and rate.
Let mm represent the hourly page output of Printer M and nn represent the hourly page output of Printer N. The total outputs give 5(2m+3n)=55005(2m + 3n) = 5500 and 4(5m+2n)=66004(5m + 2n) = 6600.
Total page output equals total operating time multiplied by the combined hourly output rate.
2
Simplify the system by dividing each equation by its respective number of hours.
First equation: 2m+3n=11002m + 3n = 1100. Second equation: 5m+2n=16505m + 2n = 1650.
Simplifying yields a standard system of linear equations representing the combined hourly rate.
3
Eliminate variable nn to solve for mm.
Multiply 2m+3n=11002m + 3n = 1100 by 22 to get 4m+6n=22004m + 6n = 2200. Multiply 5m+2n=16505m + 2n = 1650 by 33 to get 15m+6n=495015m + 6n = 4950. Subtracting the first modified equation from the second yields 11m=275011m = 2750, so m=250m = 250.
Equating the coefficients of nn allows direct elimination of nn when subtracting the equations.

Key Concept

Solving a 2x2 system of linear equations using the method of elimination
Estimated Time:1m 30s
Rate this question