SOLUTION: father can finish a certain job in 8 days while his daughter can finish the same job in 16 days. they start working together after 4 days the daughter leaves and his father alone f

Algebra ->  Rate-of-work-word-problems -> SOLUTION: father can finish a certain job in 8 days while his daughter can finish the same job in 16 days. they start working together after 4 days the daughter leaves and his father alone f      Log On


   

Question 714715: father can finish a certain job in 8 days while his daughter can finish the same job in 16 days. they start working together after 4 days the daughter leaves and his father alone finishes the work. How many days did it take the fateher to finish the job?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
They work together for 4 days
Add their rates of working
+1%2F8+%2B+1%2F16+=+x%2F4+
Multiply both sides by +16+
+2+%2B+1+=+4x+
+4x+=+3+
+x+=+3%2F4+
They complete 3/4 of the job, there
is 1/4 of the job left to do
( fraction of the job left ) / ( father's rate ) = time to finish
+%28+3%2F4+%29+%2F+%28+1%2F8+%29+=+t+
+t+=+6+
It takes the father 6 days to finish the job