SOLUTION: coleen and mariah both leave the bookstore at the same time but in opposite directions. If mariah travels 9 mph faster than coleen and after three hours they are 81 miles apart, h

Algebra ->  Rational-functions -> SOLUTION: coleen and mariah both leave the bookstore at the same time but in opposite directions. If mariah travels 9 mph faster than coleen and after three hours they are 81 miles apart, h      Log On


   

Question 1091555: coleen and mariah both leave the bookstore at the same time but in opposite directions. If mariah travels 9 mph faster than coleen and after three hours they are 81 miles apart, how fast are each traveling?
Found 2 solutions by ikleyn, addingup:
Answer by ikleyn(52814) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let x be the Coleen' speed, in miles per hour.

Then Mariah travels at the speed (x+9) mph.


The equation is

3x + 3*(x+9) = 81,

and it says that the two covered the total distance of 81 miles in 3 hours, moving toward each other.


Simplify and solve for x:

3x + 3x + 27 = 81,

6x = 81 - 27 = 54  ====>  x = 54%2F6 = 9 mph.


Answer.  Coleen' speed is 9 mph;  Mariah' speed is 9 + 9 = 18 mph.

Solved.


To see other similar solved problems / (your samples), look into the lesson
    - Travel and Distance problems for two bodies moving in opposite directions
in this site.



Answer by addingup(3677) About Me  (Show Source):
You can put this solution on YOUR website!
M = C+9
M+C = 81/3 = 27
C+9+C = 27
2C = 18
C = 9
and M = C+9 = 9+9 = 18
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Check:
3 hours at 9 mph = 27
3 hours at 18mph= 54
Total . . . . . . 81 Correct