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Question 770246: A crew of 8 people can build a concrete wall in six days. If 4 more people had joined the crew at the start, how many days would it have taken?
please show the working out, thank you
Answer by ramkikk66(644)   (Show Source):
You can put this solution on YOUR website!
A crew of 8 people can build a concrete wall in six days. If 4 more people had joined the crew at the start, how many days would it have taken?
Ans:
Principle : Time taken for completing a work is inversely proportional to number
of people. i.e. more people, less time. Less people, more time.
So a fixed volume of work is usually measured in "person-days" i.e. so many people
for so many days.
Work = people * days.
In this case, 8 people can build the wall in 6 days. So the work required to
build the wall = 8*6 = 48 person-days.
In other words, if you had only 1 person, it would take 48 days to complete the
work.
Now if you had 4 more people, number of people = 8 + 4 = 12
So to complete the same work, time taken = work / no. of people
= 48 person-days / 12 persons = 4 days.
As you can see, it takes less duration with more people.
Hope you got it :)
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