Answer: a) 456.66 s ; b) 564.3 m
Explanation:
The time taken to travel a fixed distance at constant speed is calculated by:
velocity = distance / time, thus time = distance / velocity
For the slower student:
t = 780 m / 0.9 m/s = 866.66 seconds
For the faster student:
t = 780 m / 1.9 m/s = 410.52 seconds
The difference in arrival time is 866.66 - 410.52 = 456.14 seconds.
To find the walking distance where the faster student arrives 5.5 minutes earlier, use:
distance = velocity_slow × time_1
distance = velocity_fast × time_2
The time difference corresponds to 5.5 minutes or 330 seconds.
From these, we determine:
time_1 = 627 seconds
time_2 = 297 seconds
The distance traveled in this case is 564.3 m.