To find Chen's average speed in miles per hour, you can use the formula:
\[ \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \]
- Total Distance: Chen rode 3.4 miles.
- Total Time: Chen rode for \( \frac{3}{4} \) of an hour, which is \( 0.75 \) hours.
Now substitute the values into the formula:
\[ \text{Average Speed} = \frac{3.4 \text{ miles}}{0.75 \text{ hours}} \]
To calculate this:
\[ \text{Average Speed} = \frac{3.4}{0.75} = 4.5333\ldots \text{ miles per hour} \]
Rounding to two decimal places:
\[ \text{Average Speed} \approx 4.53 \text{ miles per hour} \]
So, Chen's average speed was approximately 4.53 miles per hour.