Question

Safety regulations require that the time between airplane takeoffs (on the same runway) will be at least 2 minutes. When taking off, the run time of an airplane on the runway is 24 seconds. Planes are on average waiting 4 minutes and 24 seconds for take-off. On average there are 14 planes taking off per hour. How many planes are either on the runway or waiting to take off

Answer 1

1 plane

Explanation:

Given:

- Total rate at which planes take off TR = 14 planes / hr

- Waiting time WT = 4.4 minutes

- Run Time RT = 0.4 minutes

Find:

- How many planes are either on the runway or waiting to take off

Solution:

- Compute the total time i.e WT and RT:

Total Time TT = (WT + RT) / 60

TT = (4.4 + 0.4) / 60

TT = 4.8/60 = 0.08 hrs

- Total number of planes either waiting or on run-way are:

No. planes not taken off N = TT * TR

N = 0.08*14

N = 1.12 plane ≈ 1 plane