Final answer:
The marathon runner's approximate speed is found by converting the distance from miles to kilometers and dividing it by the time in hours. The conversion gives 42.162 km, and then dividing by 3.5 hours results in an approximate speed of 12 km/h.
Step-by-step explanation:
The question is asking to calculate the runner's approximate speed in kilometers per hour when given the distance ran in miles and the time it took in hours. First, we convert the distance from miles to kilometers by multiplying 26.2 miles by the conversion factor 1.61 kilometers per mile. Then, to find the speed in kilometers per hour, we divide the distance in kilometers by the time in hours.
So, by converting the distance to kilometers, we have 26.2 miles × 1.61 km/mile = 42.162 km. To find the speed, we divide this distance by the time, giving us 42.162 km ÷ 3.5 hours, which equals approximately to 12 km/h. Hence, the approximate speed of the marathon runner in kilometers per hour is 12 km/h, which corresponds to option B.