A plane took 1 hour longer to travel 560 miles on the first portion of a flight than it took to fly 480 miles on the second portion. If the speed was the same for each portion, what was the flying time for the second part of the trip?
2007-02-25 05:37:23 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
speed = distance/time
time for 2nd portion = x
time for 1st portion = x + 1 hr
speed is same in both portions of trip.
for 1st portion
------------------
distance = 560 miles
time = x + 1 hr (from above)
speed = distance/time = 560/(x + 1 hr)
for 2nd portion
------------------
distance = 480
time = x hr (from above)
speed = distance/time = 480/x
but speed is same as first portion, which is 560/(x + 1 hr)
therefore,
560/(x + 1) = 480/x
rearranging the terms
x/(x+1) = 480/560
reciprocating both sides
(x + 1)/x = 560/480
1 + 1/x = 56/48
solving for x
x = 6
and x is the time for 2nd portion of trip... so the answer is 6 hrs
(remember, all our time units were always in hours)
hope this helps.
Mahurshi Akilla
2007-02-25 06:26:28 · answer #1 · answered by Mahurshi Akilla 3 · 0⤊ 0⤋
560/(1 + t) = 480/t
560t = 480 + 480t
80t = 480
t = 6 hr
2007-02-25 13:49:48 · answer #2 · answered by Helmut 7 · 0⤊ 0⤋
51 minutes
2007-02-25 13:53:22 · answer #3 · answered by theprince 1 · 0⤊ 0⤋