SOLUTION: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? I'm not sure if this i

Algebra ->  Probability-and-statistics -> SOLUTION: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? I'm not sure if this i      Log On


   



Question 126952: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? I'm not sure if this is the section for this problem but if tutor can help i would greatly be appretiated,thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of working to get the final rate
In words:
(1 house) / (Sally's time) + (1 house) / (John's time)
= (1 house)/(unknown time)
%281+%2F+4%29+%2B+%281+%2F+6%29+=+1+%2F+x
multiply both sides by 12
3+%2B+2+=+12%2Fx
multiply both sides by x
5x+=+12
x+=+2.4
Together they can paint the house in 2.4 hours