Question

Between 9 AM and 10 AM one hundred airplanes departed from Newark Airport. Ten of the airplanes were delayed by an hour each. Of the remaining airplanes, half left on time and half were delayed by an average of 20 minutes. To the nearest whole minute, how long was the average flight delay

Answer 1

27 minutes

Explanation:

Given that :

Total number of planes = 100

10 planes were delayed by an hour each= 60 minutes;

Total delay time for the 10 planes = (60 * 10) = 600 minutes

Of the 90 remaining :

Half (45) left on time = no delay

(Delay2) : Half (45) experieced a average delay of 20 minutes.

Total delay time for the 45 planes = (45 * 20) = 900

Hence,

Overall delay time = (600 + 900) = 1500 minutes

Number of planes delayed = (10 +45) = 55 planes

Average flight delay :

(Overall delay time / number of planes delayed)

(1500 / 55) = 27.27

= 27 minutes ( to the nearest minute)