A plane making a 2400-mile trip was delayed 14 minutes before take-off because of bad weather. To make up for the delay, the pilot increased his airspeed and took a favorable tailwind. Thus he was able to average 6 miles per hour more than usual. Find the usual average ground speed and flying time for the trip.

v = d/t        14 mins /60 = 0.23 hours                       

let x = v

t = v/d

v =2400 miles/0.23 hours

v = 10434. 78 miles/hour  + 6 miles/hour = 10440.78 mi/hr

t = 10,440.78/2400

t = 4.35 hours x 60 mins =  4 hours and 21 mins.