Question

Difficulty: MediumTranslating and Solving Algebraic Word Problems

Two volunteer teams, Team A and Team B, are packing food boxes for a local shelter. Team A packs at a constant rate of 1515 boxes per hour and begins packing at 8:00 a.m. Team B packs at a constant rate of 2020 boxes per hour and begins packing at 9:30 a.m. If both teams pack continuously at their respective rates, how many hours after Team A begins will both teams have packed the same total number of boxes?

Answer: 6 hours

Answer

Both teams will have packed the same total number of boxes 66 hours after Team A begins.
The correct answer is 66. Let xx be the number of hours Team A packs. Team B begins 1.5 hours later, so Team B packs for x1.5x - 1.5 hours. Setting their total boxes packed equal gives 15x=20(x1.5)15x = 20(x - 1.5). Distributing yields 15x=20x3015x = 20x - 30. Subtracting 20x20x from both sides gives 5x=30-5x = -30, which simplifies to x=6x = 6.

Step-by-Step Solution

1
Define the variable for time and identify the time difference.
Let xx be the number of hours Team A packs. Since Team B starts 1 hour and 30 minutes (which is 1.51.5 hours) later, Team B's time is represented as x1.5x - 1.5 hours.
Establishing correct algebraic representations for time is necessary to set up the equation.
2
Set up an equation equating the total boxes packed by both teams.
The equation is 15x=20(x1.5)15x = 20(x - 1.5).
Since both teams pack a constant number of boxes per hour, multiplying their rate by their active time gives the total boxes packed.
3
Solve the linear equation for xx.
Distribute the 20: 15x=20x3015x = 20x - 30. Subtract 20x20x from both sides: 5x=30-5x = -30. Divide by 5-5: x=6x = 6.
Solving the equation gives the number of hours after Team A starts when their packed boxes are equal.

Key Concept

Translating real-world rates and time shifts into linear equations and solving them.
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