2 pens and 1 eraser cost $35 and 3 pens and 4 erasers cost $65. X represents the cost of 1 pen and Y

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2 pens and 1 eraser cost $35 and 3 pens and 4 erasers cost $65. X represents the cost of 1 pen and Y represents the cost of 1 eraser. Write the 2 simultaneous equations and solve.

Set up our 2 equations where cost = price * quantity:

1. 2x + y = 35
2. 3x + 4y = 65

We can solve this one of three ways:

• Substitution Method
• Elimination Method
• Cramer's Rule

No matter which method we choose, we get the same answer:

• x (cost of 1 pen) = 15
• y (cost of 1 eraser) = 5