Bob and his team consist of 8 members. They can complete the construction of one building in 7 days. They get a contract to construct 4 buildings. However, Bob gets injured after constructing 2 buildings and other members constructed the remaining two buildings. How many days will it take to complete the construction of the 4 buildings?
Answers
Answer:
Any worker day question can be solved with the concept of man-days.
As it takes 3 days for 10 workers to build a house. This implies a house needs 30 man-days to be built up.
Therefore, 4 houses will need 120 man-days.
Now, we have 15 workers.
Hence we would need 8 days (120/15) to build 4 houses.
It will take 27 days to complete the construction of the 4 buildings.
Given,
Number of members = 8
Time is taken to complete the construction of 1 building = 7 days
Total number of buildings to be constructed = 4
2 buildings are constructed by 8 members
Rest 2 buildings are constructed by 7 members
To Find,
Total number of days taken to complete the construction of the 4 buildings
Solution,
For the initial 2 buildings, 8 members will complete the construction in 7 x 2 = 14 days. (By unitary method)
Then, we have the formula,
M1W1/D1 = M2W2/D2
M is the total number of people who worked for work W in D days.
(8 x 2)/14 = (7 x 2)/D2
We have put the values accordingly as case 1 and case 2.
16/14 = 14/D2
D2=14x14/16 days
D2=196/16 days
D2 ≅ 13 days
Hence, it took around 13 days for 7 members to complete the construction of the rest of 2 buildings.
So, total number of days for the construction of 4 buildings = 14 + 13 = 27 days. This is the final answer.
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