The answer is d = 16 kilometers. This means that Serena ran a total of 16 kilometers during her training run.
Step-by-step explanation:
To find the total distance that Serena ran, we can use the formula d = rt, where d represents the distance, r represents the rate, and t represents the time. We are given that r = 8 kilometers per hour and t = 2 hours. Therefore, we can plug these values into the formula and solve for d:
d = rt d = 8 * 2 d = 16