To find the percent error, you can use the formula:
\[ \text{Percent Error} = \left( \frac{\text{Actual Value} - \text{Predicted Value}}{\text{Predicted Value}} \right) \times 100 \]
In this case:
- Actual Value: Mark and Matthew's finishing time = 53 minutes
- Predicted Value: Their predicted finishing time = 60 minutes
Now, let's plug in the values:
\[ \text{Percent Error} = \left( \frac{53 - 60}{60} \right) \times 100 \]
First, calculate the difference:
\[ 53 - 60 = -7 \]
Now, divide by the predicted value:
\[ \frac{-7}{60} \approx -0.1167 \]
Now multiply by 100 to get the percentage:
\[ -0.1167 \times 100 \approx -11.67 \]
Rounding to the nearest tenth, the percent error is approximately:
\[ -11.7% \]
Since the percent error is negative, it indicates they finished faster than predicted. When expressing percent error, you can refer to this as an 11.7% underestimation of the predicted time.