Question

Fill in the blanks!

Time Elapsed (hr) - Distance Run (mi)
2 - 13.5
4 - 27.5
7 - 48.5

Larry recorded his time as he ran.
What was his average speed from hour 2 to hour 4? _
What was his average speed from hour 4 to hour 7? _
Did he speed up, slow down, or stay the same? _

Answer 1

To find the average speed over the given time intervals, you can use the formula for average speed:

\[
\text{Average Speed} = \frac{\text{Distance}}{\text{Time}}
\]

### 1. From hour 2 to hour 4:

- **Distance at hour 2:** 13.5 miles
- **Distance at hour 4:** 27.5 miles
- **Distance covered from hour 2 to hour 4:**
\[
27.5 - 13.5 = 14 \text{ miles}
\]
- **Time duration from hour 2 to hour 4:**
\[
4 - 2 = 2 \text{ hours}
\]
- **Average Speed from hour 2 to hour 4:**
\[
\text{Average Speed} = \frac{14 \text{ miles}}{2 \text{ hours}} = 7 \text{ miles per hour}
\]

### 2. From hour 4 to hour 7:

- **Distance at hour 4:** 27.5 miles
- **Distance at hour 7:** 48.5 miles
- **Distance covered from hour 4 to hour 7:**
\[
48.5 - 27.5 = 21 \text{ miles}
\]
- **Time duration from hour 4 to hour 7:**
\[
7 - 4 = 3 \text{ hours}
\]
- **Average Speed from hour 4 to hour 7:**
\[
\text{Average Speed} = \frac{21 \text{ miles}}{3 \text{ hours}} = 7 \text{ miles per hour}
\]

### Conclusion:
- Average speed from hour 2 to hour 4: **7 miles per hour**
- Average speed from hour 4 to hour 7: **7 miles per hour**

### Did he speed up, slow down, or stay the same?
Since the average speeds over both time intervals are the same (7 miles per hour), Larry stayed the same.