Answer:
58.7 ft/sec
Explanation:
The train traveled half a mile.
1 mile = 5280 ft
0.5 mile = 0.5 * 5280 ft = 2640 ft
A time from 10 sec to 55 sec is 55 sec - 10 sec = 45 seconds.
2640 ft in 45 seconds
speed = distance/time
speed = 2640 ft / 45 sec = 58.6666... ft/sec
Answer: speed = 58.7 ft/sec