一列長為500米的火車，以時速60公里穿過一條長達1000米

AB is the length of the tunnel

A B C
===============
e******f e******f

length of AC = length of tunnel +length of the train
length = 1000 m + 500 m = 1500 m = 1.5 km (1 km = 1000 m)

speed of the train = 60 km/h

time required = distance / speed
= 1.5 km / 60 km/h =0.025 h

0.025 h = 0.025 x 60 min.
= 1.5 min. = 1.0 min + 0.5 min
= 1 min. 30 s (Note : half of a min. = 30 s)

Time required for the point f to move from A to C is 1 min. 30 sec.

Note:
x represents multiply
f is the front part of the train
e is the end part of the train

Drawing is not to scale.

1000米=1km
The speed of the train:60km/h
________________
1500m/60(km/h)
1.5/60
=1/40 hour(which means 1.5minutes)
______________

你點得出這個答案！？

30min ok?- -