SOLUTION: Grace can clean an entire house in 8 hours. Cherry can do the same job in 6 hours. After 2 hours of working together, Grace left and Cherry finished cleaning. How long did it take

Algebra ->  Test -> SOLUTION: Grace can clean an entire house in 8 hours. Cherry can do the same job in 6 hours. After 2 hours of working together, Grace left and Cherry finished cleaning. How long did it take       Log On


   

Question 1103149: Grace can clean an entire house in 8 hours. Cherry can do the same job in 6 hours. After 2 hours of working together, Grace left and Cherry finished cleaning. How long did it take Cherry to finish the job?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Rate x Time=Output.
.
.
.
R%5BG%5D%2A8=1
R%5BG%5D=1%2F8
.
.
R%5BC%5D%2A6=1
R%5BC%5D=1%2F6
So together,
%28R%5BG%5D%2BR%5BC%5D%29%2A2=%281%2F8%2B1%2F6%292=1%2F4%2B1%2F3=3%2F12%2B4%2F12=7%2F12
So then,
1-7%2F12=5%2F12
5%2F12 still needs to be done by Cherry.
R%5BC%5D%2At%5BC%5D=5%2F12
%281%2F6%29%2At%5BC%5D=5%2F12
t%5BC%5D=%285%2F12%29%286%29
t%5BC%5D=5%2F2
Cherry needed 2%261%2F2 hours to finish.