Bethany, Morgan, and Taylor all go to the local activity center after school. Each girl uses a different form of transportation to travel the six miles from the school to the activity center. Bethany walks, Morgan rides her bike, and Taylor takes the bus. Bethany leaves directly after school, and her distance can be modeled by the equation y=4x . Morgan leaves half an hour after Bethany, and her distance can be modeled by the equation y=8x−4 . Taylor leaves one hour after Bethany, and her distance can be modeled by the equation y=20x−20 . Use the linear function graph. Which girl arrives at the activity center first?

1 answer

To determine which girl arrives at the activity center first, we need to find the time it takes each girl to reach the activity center based on their distance equations.

  1. Bethany's Distance Equation:

    • Equation: \( y = 4x \)
    • Here, \( y \) represents the distance traveled in miles, and \( x \) represents the time in hours since she left school.
    • She travels at a speed of 4 miles per hour.

    To find the time she takes to travel 6 miles: \[ 6 = 4x \implies x = \frac{6}{4} = 1.5 \text{ hours} \] So, Bethany arrives at the activity center 1.5 hours after leaving school.

  2. Morgan's Distance Equation:

    • Equation: \( y = 8x - 4 \)
    • Morgan leaves half an hour after Bethany, meaning if Bethany starts at \( t = 0 \), Morgan starts at \( t = 0.5 \) hours.
    • She travels at a speed of 8 miles per hour.

    To find the time she takes to travel 6 miles: \[ 6 = 8x - 4 \implies 10 = 8x \implies x = \frac{10}{8} = 1.25 \text{ hours (since she starts at 0.5 hours, her total time to reach is 1.25 + 0.5 = 1.75 hours)} \] Morgan arrives at the activity center 1.75 hours after Bethany leaves (1.25 hours traveling + 0.5 hours waiting).

  3. Taylor's Distance Equation:

    • Equation: \( y = 20x - 20 \)
    • Taylor leaves one hour after Bethany, so if Bethany starts at \( t = 0 \), Taylor starts at \( t = 1 \) hour.
    • She travels at a speed of 20 miles per hour.

    To find her time to travel 6 miles: \[ 6 = 20x - 20 \implies 26 = 20x \implies x = \frac{26}{20} = 1.3 \text{ hours (since she starts at hour 1, her total time to reach is 1.3 + 1 = 2.3 hours)} \] Taylor arrives at the activity center 2.3 hours after Bethany leaves (1.3 hours traveling + 1 hour waiting).

Summary of Arrival Times:

  • Bethany: 1.5 hours after leaving
  • Morgan: 1.75 hours after leaving
  • Taylor: 2.3 hours after leaving

Therefore, Bethany arrives at the activity center first, in 1.5 hours after she leaves school.