The graph shows the number of good deeds performed at a fast food drive thru over the course of a weekend. Customers were "paying it forward" by purchasing a food item for the person behind them in line.

Complete the table (based on the graph) and write an exponential function rule.
\table[[Time (Hours),Number of Good Deeds],[0,2],[1,6],[2,18]]
Your table is correct! Now write the equation.
Is my table correct?
y=

1 answer

To determine if your table is correct and to find the exponential function rule, let's analyze the values given and look for a pattern.

From the table:

  • At \( t = 0 \) hours, \( y = 2 \)
  • At \( t = 1 \) hour, \( y = 6 \)
  • At \( t = 2 \) hours, \( y = 18 \)

The relationship suggests that the number of good deeds is increasing exponentially. We can assume the general form of the exponential function is:

\[ y = a \cdot b^t \]

where:

  • \( a \) is the initial amount of good deeds,
  • \( b \) is the growth factor,
  • \( t \) is the time in hours.

From the data provided:

  • When \( t = 0 \): \[ y = a \cdot b^0 = a \quad \text{so } \quad a = 2 \]
  • When \( t = 1 \): \[ y = 2 \cdot b^1 = 6 \quad \Rightarrow \quad b = \frac{6}{2} = 3 \]
  • When \( t = 2 \): \[ y = 2 \cdot b^2 = 18 \quad \Rightarrow \quad 2 \cdot b^2 = 18 \quad \Rightarrow \quad b^2 = 9 \quad \Rightarrow \quad b = 3 \]

So both calculations give us the same growth factor \( b = 3 \).

Now substituting \( a \) and \( b \) back into the general equation, we have:

\[ y = 2 \cdot 3^t \]

Thus, the equation for the exponential function that describes the number of good deeds over time is:

\[ y = 2 \cdot 3^t \]

Summary

Your table appears to be correct:

  • Table:

    • Time (Hours): 0, 1, 2
    • Number of Good Deeds: 2, 6, 18
  • Exponential Function Rule: \[ y = 2 \cdot 3^t \]