SOLUTION: Philip can dry mop a wet basketball court in 45 mins; while James can do the same job in 30 mins. They first worked together on the job for 10 mins and then Philip was transferred

Algebra ->  Customizable Word Problem Solvers  -> Mixtures -> SOLUTION: Philip can dry mop a wet basketball court in 45 mins; while James can do the same job in 30 mins. They first worked together on the job for 10 mins and then Philip was transferred       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 796663: Philip can dry mop a wet basketball court in 45 mins; while James can do the same job in 30 mins. They first worked together on the job for 10 mins and then Philip was transferred to mop another court. How many more mins did it take James to finish dry mopping the court alone?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Philip's rate is ( 1 court ) / ( 45 min )
James's rate is ( 1 court ) / ( 30 min )
-------------------------------
What fraction of the court did they finish in 10 min ?
Let +x+ = that fraction
+1%2F45+%2B+1%2F30+=+x%2F10+
Multiply both sides by +90+
+2+%2B+3+=+9x+
+x+=+5%2F9+
5/9 of the court got mopped
That means 4/9 of the court was left
----------------
Let +t+ = James time in minutes to mop 4/9 of the court
+1%2F30+=+%284%2F9%29+%2F+t+
+1%2F30+=+4+%2F+%289t%29+
Multiply both sides by +270t+
+9t+=+4%2A30+
+9t+=+120+
+t+=+13.333+ min
+.333%2A60+=+20+
It takes James 13 min and 20 sec to finish
check:
+1%2F30+=+%284%2F9%29+%2F+t+
+1%2F30+=+.4444+%2F+13.333+
+1%2F30+=+1%2F30+
OK