SOLUTION: Together, Andy and Ben can re-roof a certain house in six days. When Ben works alone, it takes him 9 days longer than when Andy works by himself. How long does it take each person

Question 1097168: Together, Andy and Ben can re-roof a certain house in six days. When Ben works alone, it takes him 9 days longer than when Andy works by himself. How long does it take each person to re-roof the same house independently?

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = Andy's time in days to re-roof a house
Andy's rate of working is:
[ 1 house re-roofed ] / [ t days ]
Ben's rate of working is:
[ 1 house re-roofed ] / [ t + 9 days ]
Their rate working together:
[ 1 house re-roofed ] / [ 6 days ]
--------------------------------------
Add their individual rates to get their rate working together

Multiply both sides by

by looking at it
( can't use the negative solution )
and

------------------------
Andy takes 9 days working alone
Ben takes 18 days working alone
---------------------------------
check:

OK
RELATED QUESTIONS
Tom and Jane can clean the house together in 4 hours. When Tom works alone, it takes him... (answered by josgarithmetic)

A father and his son clean the house together in 6 hours. When son works alone, it take... (answered by josmiceli)

A father and his son can clean the house together in 8 hours. When the son works alone,... (answered by josgarithmetic,ikleyn)

Can someone please help me to solve this problem. A father and his son can clean the... (answered by stanbon,mathstutor494)

a father and his son can clean the house together in 6 hours. When the son works alone,... (answered by stanbon)

I really Need Help With My Grade 9 Algebraic Equations and its for 20 points in every... (answered by richwmiller)

When workers A and B work together, they can finish the flooring of a house in 6... (answered by josgarithmetic,stanbon)

A painter can paint a house in 3 days. When his helper works with him, both men can paint (answered by rfadrogane)

two workmen can paint a house together in 6 and 1/3 days. in how many days can each paint (answered by stanbon,richwmiller)