SOLUTION: Jiga can finish painting his house in 24 minutes. If his brother will help him they will finish it. in 15 minutes. How long will it take his brother to paint it alone?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Jiga can finish painting his house in 24 minutes. If his brother will help him they will finish it. in 15 minutes. How long will it take his brother to paint it alone?      Log On


   

Question 831090: Jiga can finish painting his house in 24 minutes. If his brother will help him they will finish it. in 15 minutes. How long will it take his brother to paint it alone?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = brother's time in minutes to paint it alone
Add their rates of painting to get their
rate working together
( 1 house ) / ( 24 min ) + ( 1 house ) / ( t min ) = ( 1 house ) / ( 15 min )
+1%2F24+%2B+1%2Ft+=+1%2F15+
Multiply both sides by +24%2A15t+
+15t+%2B+15%2A24+=+24t+
+9t+=+360+
+t+=+40+
It will take his brother 40 min working alone