What is one main impediment to regional economic integration? identical political ideologies reduced immigration loss of nationa
1 answer:
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Answer:
The time it will take to roof the house if the homeowner helps the roofer is 2.25 days.
Explanation:
The time it takes the homeowner to roof his house is, <em>X</em> = 9 days.
The time it takes the professional roofer to roof the house is, <em>Y</em> = 3 days.
Then if the the homeowner helps the roofer, the time it will take to roof the house is, <em>X</em> + <em>Y</em>.
The work done by the homeowner in 1 day is, .
The work done by the professional roofer in 1 day is,
The work done in 1 day if both the homeowner and the professional roofer work together is,
⇒
Then the number of days it takes to roof the house if both the homeowner and the professional roofer work together, i.e. <em>X</em> + <em>Y</em> is,
⇒
Thus, the time it will take to roof the house if the homeowner helps the roofer is 2.25 days.