Question

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%**.