For this issue, the answer is clarified as the system takes in energy (+). The surroundings contribute 84 KJ of work. Whenever a system is receiving work from its surroundings, the value will be positive. Therefore, it sums to 12.4 KJ + 4.2 = 16.6 KJ.
Isn't it necessary to multiply it?
Answer:
(a) 16.777 miles
(b) Yes, he exceeded the speed limit
Explanation:
(a)
We need to perform the necessary calculations to convert kilometers to miles:

Thus, the distance of the trip in miles is:

(b)
Next, we will compute the man's speed during the journey:

Before that, we must convert minutes to hours:

The resulting speed is:

Consequently:

Thus, it can be concluded that the driver was speeding