Question

Difficulty: MediumSystems of Linear Equations

An electronics manufacturing plant produces two types of circuit modules: Module X and Module Y. Producing one Module X requires 33 minutes on Machine A and 55 minutes on Machine B. Producing one Module Y requires 44 minutes on Machine A and 22 minutes on Machine B. During a certain shift, Machine A was operated for a total of 230230 minutes and Machine B was operated for a total of 220220 minutes. If both machines operated at full capacity with no idle time, how many Module X units were produced?

Answer: 30 units

Answer

30
Formulating equations from the machine times gives 3x+4y=2303x + 4y = 230 for Machine A and 5x+2y=2205x + 2y = 220 for Machine B. Multiplying the second equation by 22 yields 10x+4y=44010x + 4y = 440. Subtracting 3x+4y=2303x + 4y = 230 from 10x+4y=44010x + 4y = 440 eliminates yy and yields 7x=2107x = 210, which solves to x=30x = 30.

Step-by-Step Solution

1
Define variables for the unknown quantities.
Let xx be the number of Module X units produced, and let yy be the number of Module Y units produced.
Representing unknown quantities with algebraic variables allows for model formulation.
2
Formulate a system of linear equations from the machine time constraints.
Machine A equation: 3x+4y=2303x + 4y = 230
Machine B equation: 5x+2y=2205x + 2y = 220
The total operational time on each machine equals the sum of times spent producing each module type.
3
Multiply the Machine B equation by 22 to enable elimination of yy.
2×(5x+2y)=2×220    10x+4y=4402 \times (5x + 2y) = 2 \times 220 \implies 10x + 4y = 440
Matching the coefficient of yy with the first equation (4y4y) allows elimination via subtraction.
4
Subtract the Machine A equation from the modified Machine B equation and solve for xx.
(10x+4y)(3x+4y)=440230    7x=210    x=30(10x + 4y) - (3x + 4y) = 440 - 230 \implies 7x = 210 \implies x = 30
Subtracting eliminates yy directly, leaving a single linear equation in terms of xx.

Key Concept

Solving a system of two linear equations in two variables using elimination
Estimated Time:1m 30s
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