SOLUTION: two planes leave Chicago. ONE HEADS WEST AT 410 MPH AT 10:00 AND THE OTHER HEADS EAST AT 370 MPH 15 MINUTES LATER. At what time will the planes be 4119.5 miles apart?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: two planes leave Chicago. ONE HEADS WEST AT 410 MPH AT 10:00 AND THE OTHER HEADS EAST AT 370 MPH 15 MINUTES LATER. At what time will the planes be 4119.5 miles apart?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 985664: two planes leave Chicago. ONE HEADS WEST AT 410 MPH AT 10:00 AND THE OTHER HEADS EAST AT 370 MPH 15 MINUTES LATER. At what time will the planes be 4119.5 miles apart?
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!
DISTANCE=RATE%2ATIME, TIME=DISTANCE%2FRATE

15 minutes = 0.25 hours

First plane travels 410(0.25) = 102.5 miles during 1st 15 minutes

They are 102.5 miles apart when the second plane starts.

Their rate of separation is 410+370 = 780 MPH

They are already separated by 102.5 miles.  

We want to know when they will have separated 4119.5-102.5 or 4017 more
miles:

TIME=DISTANCE%2FRATE=4017%2F780=5.15 hours or 5 hours 9 minutes after

2nd plane takes off.

Edwin