SOLUTION: 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, wh

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: 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, wh      Log On


   

Question 86514: 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?
A)8 hours
B)7 hours
C)5 hours
D) 6 hours
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
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?
A)8 hours
B)7 hours
C)5 hours
D) 6 hours

Make this chart.


                     |  DISTANCE |    RATE   |  TIME  |
1st portion of trip  |           |           |        |
2nd portion of trip  |           |           |        |

Let t = the flying time for the second part of the trip.
So fill in "t" for the time for the 2nd portion:


                     |  DISTANCE |    RATE   |  TIME  |
1st portion of trip  |           |           |        |
2nd portion of trip  |           |           |    t   |

Now read this:

>>...took 1 hour longer.....on the first portion
of a flight than it took.....on the second 
portion...<<

So we fill in t+1 for the time of the first portion.


                     |  DISTANCE |    RATE   |  TIME  |
1st portion of trip  |           |           |   t+1  |
2nd portion of trip  |           |           |    t   |

Now read this:

>>...560 miles on the first portion.....480 miles on the 
second portion...<< 

Now fill in those two distances:

                     |  DISTANCE |    RATE   |  TIME  |
1st portion of trip  |     560   |           |   t+1  |
2nd portion of trip  |     480   |           |    t   |

Now use RATE+=+%28DISTANCE%29%2F%28TIME%29 to fill in the rates:

                     |  DISTANCE |    RATE   |  TIME  |
1st portion of trip  |     560   |     560%2F%28t%2B1%29  |   t+1  |
2nd portion of trip  |     480   |     480%2Ft   |    t   |

Now that we have the chart all filled in, we look for what
we haven't used. That is this:

>>...the speed was the same for each portion...<<

So we set two rates (speeds) equal:

560%2F%28t%2B1%29 = 480%2Ft

Can you solve that?  Answer t = 6 hours 

Edwin