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.Com
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(52817)   (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 =  = 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)   (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
--------------------------
Check:
3 hours at 9 mph = 27
3 hours at 18mph= 54
Total . . . . . . 81 Correct
RELATED QUESTIONS

Skyler and Roberto both leave the bookstore at the same time, but in opposite directions. (answered by robertb)
Alexis and Julia both leave the bookstore at the same time, but in opposite directions.... (answered by josgarithmetic)
Alexis and Rosa both leave the bookstore at the same time, but in opposite directions. If (answered by Boreal)
Andrea and Stacy both leave the coffee shop at the same time, but in opposite directions. (answered by solver91311)
Brendan and Andrew both leave the library at the same time, but in opposite directions.... (answered by greenestamps)
Frank and Michael both leave the park at the same time, but in opposite directions. If... (answered by stanbon)
Diego and Ken both leave the mall at the same time, but in opposite directions. If Ken... (answered by fractalier)
Erin and Jamie both leave the park at the same time, but in opposite directions. If Jamie (answered by jorel1380)
Aaron and Logan both leave the restaurant at the same time, but in opposite directions.... (answered by josmiceli)