<u>Answer:</u> The speed of the dog is 8 ft/s
<u>Explanation:</u>
Speed is defined as the ratio of distance traveled to the time taken.
To calculate the distance traveled by boat, we use the equation:

We are given:
Distance traveled by dog = 40 ft
Time taken = 5 seconds
Putting values in above equation, we get:

Hence, the speed of the dog is 8 ft/s