Safety regulations require that the time between airplane takeoffs (on the same runway) will be at least 3 minutes. When taking off, the run time of an airplane on the runway is 45 seconds. Planes are on average waiting 4 minutes and 15 seconds for take-off. On average there are 15 planes taking off per hour. How many planes are either on the runway or waiting to take off

WIP = 1.25

As here  1 plane either on the runway or waiting to take off

Explanation:

given data

time between airplane takeoffs = 3 min

run time runway = 45 seconds

average waiting take off  =  4 minutes and 15 seconds

solution

we know that here

WIP = TR × TT     .........................1

here WIP is number of plane waiting or on the runway

and TR is number of planes taking off per hour and  TT is time for waiting and the runway

so here TR is 15 plans per hour.

and

TT = hr  = hr

so put value in equation 1 we get

WIP = 15 ×  

WIP = 1.25

so here is 1 plane either on the runway or waiting to take off

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