Final answer:
The upper bound for speed is approximately 22.5 km/min and the lower bound is approximately 22.0 km/min, when calculated with the given bounds for distance and time. None of the options provided in the question are correct.
Step-by-step explanation:
The formula to connect speed (s), distance (d), and time (t) is s = d/t. To find the upper and lower bounds for speed, we need to take into account the possible variances in the given distances and times. Since distances and times are given to two significant figures, their smallest possible increments are in the last given decimal place.
For the distance of 160 km (to 2 s.f.), the lower bound is 159.5 km and the upper bound is 160.5 km.
For the time of 7.2 minutes (to 2 s.f.), the lower bound is 7.15 minutes and the upper bound is 7.25 minutes.
To find the upper bound for speed, we divide the upper bound for distance by the lower bound for time:
s = 160.5 km / 7.15 min ≈ 22.45 km/min
To find the lower bound for speed, we divide the lower bound for distance by the upper bound for time:
s = 159.5 km / 7.25 min ≈ 22.00 km/min
So none of the given options A, B, C, or D are correct. However, we can deduce that since the question may assume rounding to the nearest tenth for speed, the upper bound could be rounded to 22.5 km/min and the lower bound to 22.0 km/min.