(n^4 - 1) = (n^2 - 1) (n^2 +1) = (n - 1) (n + 1) (n^2 + 1)
Answer:
2 minutes
Step-by-step explanation:
The front of the train enters the tunnel and travels 1 km before the rear of the train enters the tunnel. Thus, the total distance traveled by the front of the train is 2 km, and this is covered in a certain number of hours:
Since distance = rate times time, time = distance / rate. In this particular case we have:
2 km
time = distance / rate = ------------------- = (1/30) hr
60 km/hr
(1/30) hr converts to 2 minutes, since 1 hr = 60 minutes
Answer:
Step-by-step explanation:
1 foot = 12 inches
length of board in inches = 8 ft × (12 in)/ft = 96 in
length of cut in inches = 5 ft + 8 in = 5 ft × (12 in)/ft + 8 in = 60 in + 8 in = 68 in.
96 - 68 = 28 inches left