Bob plans to buy books at a book fair. She thinks she will need $30 to purchase the books. She only spends $19.75 find the percentage error in her prediction round your answer to the nearest whole number.

Answer 1

To find the percentage error in Bob's prediction, we can use the following formula for percentage error:

\[ \text{Percentage Error} = \left( \frac{\text{Estimated Value} - \text{Actual Value}}{\text{Estimated Value}} \right) \times 100 \]

In this case, the estimated value is $30 and the actual value spent is $19.75.

1. Calculate the difference between the estimated value and the actual value: \[ 30 - 19.75 = 10.25 \]

2. Use the difference in the percentage error formula: \[ \text{Percentage Error} = \left( \frac{10.25}{30} \right) \times 100 \]

3. Calculate: \[ \frac{10.25}{30} \approx 0.34167 \] \[ 0.34167 \times 100 \approx 34.17 \]

4. Round to the nearest whole number: \[ \text{Percentage Error} \approx 34% \]

Therefore, the percentage error in Bob's prediction is 34%.