Kelly and Greta are asked to write an equation for the scenario below.

“One person was able to plant 4 trees in the same amount of time that 5 people working together were able to plant 20 trees.”

The girls agree that x represents the number of people working and y represents the number of trees planted. Kelly wrote the equation y = one-fourth x, and Greta wrote the equation y = 4 x. Which person is correct, and why?
Kelly is correct; each person plants One-fourth more trees than the person before them.
Kelly is correct; 1 = one-fourth times 4 and 5 = one-fourth times 20.
Greta is correct; each person plants 4 more trees than the person before them.
Greta is correct; 4 = 4 times 1 and 20 = 4 times 5.

1 answer

To analyze the scenario carefully:

  1. The scenario states that "one person was able to plant 4 trees." This means that if 1 person works, they plant 4 trees.

  2. The scenario also states that "5 people working together were able to plant 20 trees." This implies that when you have 5 people, they collectively plant 20 trees.

Now, let’s break down the equations suggested by Kelly and Greta:

  • Kelly's equation: \( y = \frac{1}{4}x \) suggests that each person plants one-fourth of the number of trees represented by \( x \). This interpretation does not accurately reflect the situation, since we know from the scenario that 1 person plants 4 trees and not one-fourth of the trees.

  • Greta's equation: \( y = 4x \) suggests that for each person \( x \), they plant 4 trees. This matches the provided information: if 1 person plants 4 trees (when \( x = 1 \), \( y = 4 \)) and if there are 5 people, that would be \( y = 4(5) = 20 \), which aligns with the scenario given that 5 people plant 20 trees.

Given the analysis, Greta is correct because her equation accurately represents how many trees are planted based on the number of people working. The correct reasoning is represented through the understanding that each person contributes to planting 4 more trees, resulting in her equation \( y = 4x \).

Therefore, the correct option is Greta is correct; \( 4 = 4 \) times \( 1 \) and \( 20 = 4 \) times \( 5 \).