Percy works two part-time jobs to help pay for college classes. On Monday, he works 3 hours at the library and 2 hours at the coffee cart and earns $36.50. On Tuesday, he works 2 hours at the library and 5 hours at the coffee cart and earns $50. His hourly wage at the library, x, and hourly wage at the coffee cart, y, can be determined using the system of equations below.

3x + 2y = 36.50
2x + 5y = 50.00
At which job does Percy earn the greater hourly wage? How much does Percy earn each hour at this job?

Percy earns a greater hourly wage of $7.00 at the library.
Percy earns a greater hourly wage of $7.00 at the coffee cart.
Percy earns a greater hourly wage of $7.50 at the library.
Percy earns a greater hourly wage of $7.50 at the coffee cart.

1 answer

To determine at which job Percy earns the greater hourly wage, we need to solve the system of equations given:

  1. \( 3x + 2y = 36.50 \) (Equation 1)
  2. \( 2x + 5y = 50.00 \) (Equation 2)

We can solve this system using substitution or elimination. Here, we'll use the elimination method.

First, let's manipulate Equation 1 to eliminate one of the variables. We can multiply Equation 1 by 5 and Equation 2 by 2 to align the coefficients of \(y\):

\[ 5(3x + 2y) = 5(36.50) \implies 15x + 10y = 182.50 \quad (Equation 3) \]

\[ 2(2x + 5y) = 2(50.00) \implies 4x + 10y = 100.00 \quad (Equation 4) \]

Now we subtract Equation 4 from Equation 3:

\[ (15x + 10y) - (4x + 10y) = 182.50 - 100.00 \]

This simplifies to:

\[ 11x = 82.50 \]

Now divide both sides by 11:

\[ x = \frac{82.50}{11} = 7.50 \]

Now that we have \(x\) (the hourly wage at the library), we need to find \(y\) (the hourly wage at the coffee cart). We can substitute \(x\) back into either Equation 1 or Equation 2. We will use Equation 1:

\[ 3(7.50) + 2y = 36.50 \]

This simplifies to:

\[ 22.50 + 2y = 36.50 \]

Subtract 22.50 from both sides:

\[ 2y = 14.00 \]

Now divide by 2:

\[ y = 7.00 \]

So, we found \(x = 7.50\) (library) and \(y = 7.00\) (coffee cart).

Percy earns a greater hourly wage of $7.50 at the library.

Therefore, the answer is: Percy earns a greater hourly wage of $7.50 at the library.