Problema Solution
an airline runs a cummuter flight between Portland, oregon and seattle, washington, which are 145 miles apart. If the average speed of the plane could be increased by 30 miles per hour, the travel time would be decreased by 12 minutes. what airspeed is required to obtain this decrease in travel time?
Answer provided by our tutors
let the initial speed be x
so nominal time would be 145/x.
Now increased speed = 30 + x
time taken with increased speed = 145/(30+x)
145/x - 145/(30+x) = 12/60
x(x+30) = 5(145)(30)
x^2 + 30x - 145*150 = 0
x = (-30 + 296.4)/2 = 133.1miles/hour
Increased speed = 133.1 + 30 =163.1 miles/hour