Question 807051
One plane flies east from Seattle to Chicago, and another west from Chicago to Seattle.
 The two cities are 1800 miles apart. Both planes leave at 12 pm EST, but the flight to Chicago lands at 3pm EST and the flight to Seattle lands at 5 pm EST.
 how far East of Seattle were the planes when they passed each other?
:
From the given information we can find the actual speed of each aircraft
Eastbound travel time: 3hrs, {{{1800/3}}} = 600 mph
Westbound travel time: 5hrs, {{{1800/5}}} = 360 mph
:
Let d = the meeting distance from Seattle
then
(1800-d) = the meeting point from Chicago
:
Write a time equation; time = dist/speed
Both aircraft had the same travel time
{{{d/600}}} = {{{((1800-d))/360}}}
cross multiply
360d = 600(1800-d)
360d = 1080000- 600d
360d + 600d = 1080000
960d = 1080000
d = {{{1080000/960}}}
d = 1125 mi from Seattle when they met
:
:
Check this by finding the travel times of each, they should be the same.
Eastbound: 1125/600 = 1.875 hrs
Westbount: (1800-1125)/360 = 1.875 hrs