Question

Difficulty: EasyLinear Equations in Two Variables

A community garden charges a one-time registration fee plus a monthly fee to plot and maintain a garden bed. The total cost, yy, in dollars, of maintaining a garden bed for xx months is given by the equation y=15x+45y = 15x + 45. If a gardener spent a total of 165165 dollars, for how many months did they maintain the garden bed?

Answer: 8 months

Answer

The correct answer is 8. Setting the total cost y equal to 165 in the linear equation yields 165 = 15x + 45. Subtracting 45 from both sides gives 120 = 15x, and dividing by 15 results in x = 8 months.
To find the number of months the gardener maintained the garden bed, substitute the total spent, 165165, for yy in the equation y=15x+45y = 15x + 45. This results in 165=15x+45165 = 15x + 45. Subtracting 4545 from both sides of the equation yields 120=15x120 = 15x. Dividing both sides by 1515 gives x=8x = 8. Thus, the garden bed was maintained for 8 months.

Step-by-Step Solution

1
Substitute 165 for y in the equation.
165=15x+45165 = 15x + 45
The variable y represents the total cost in dollars, which is given as 165.
2
Subtract 45 from both sides of the equation.
120=15x120 = 15x
This isolates the variable term by subtracting the constant registration fee.
3
Divide both sides of the equation by 15.
x=8x = 8
This solves for x, the number of months.

Key Concept

Solving for a variable in a linear equation representing a real-world scenario.
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