Question

It took Sue 1 3/4 hours to walk 5 1/4 miles. How fast, on average, was she walking?

Answer 1

To find Sue's average walking speed, we need to divide the total distance she walked by the total time it took her.

1. **Convert the distance and time into improper fractions**:

- For distance:
\( 5 \frac{1}{4} \) miles = \( \frac{5 \times 4 + 1}{4} = \frac{20 + 1}{4} = \frac{21}{4} \) miles.

- For time:
\( 1 \frac{3}{4} \) hours = \( \frac{1 \times 4 + 3}{4} = \frac{4 + 3}{4} = \frac{7}{4} \) hours.

2. **Calculate the average speed**:

Average speed = \( \frac{\text{Distance}}{\text{Time}} \)

\[
\text{Average Speed} = \frac{\frac{21}{4} \text{ miles}}{\frac{7}{4} \text{ hours}}
\]

When dividing by a fraction, we multiply by its reciprocal:

\[
\text{Average Speed} = \frac{21}{4} \times \frac{4}{7}
\]

The \( 4 \)s cancel out:

\[
\text{Average Speed} = \frac{21}{7} = 3 \text{ miles per hour}
\]

Thus, Sue's average walking speed was **3 miles per hour**.