In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: an intern wants to label folders with numbers using digit stickers only . if the intern uses 999 stickers , how many folders have been numbered ? ( the numbers of the folders are consecutive and the number of the first folder is 1 ) .
Options: a ) 287 , b ) 369 , c ) 370 , d ) 371 , e ) 430
[A]: b

[Q]: Problem: a searchlight on top of the watchtower makes 2 revolutions per minute . what is the probability that a man appearing near the tower will stay in the dark for at least 5 seconds ?
Options: a ) 5 / 6 , b ) 5 / 12 , c ) 7 / 12 , d ) 11 / 12 , e ) 11 / 15
[A]: a

[Q]: Problem: the length of the bridge , which a train 140 meters long and travelling at 45 km / hr can cross in 30 seconds , is :
Options: a ) 230 , b ) 244 , c ) 245 , d ) 238 , e ) 235
[A]:
e