By working 12 hours a day, 90 people can complete a work in 16 days. How much work will be left after 24 days if 70 people work for 8 hours per day?
- A8
3
- B9
2
- C9
7
- D8
5
Solution & Step-by-step Explanation
Let the total initial work be W
1
=1.
Using the chain rule formula:
W
1
M
1
×D
1
×H
1
=
W
2
M
2
×D
2
×H
2
Where:
M
1
=90, D
1
=16, H
1
=12, W
1
=1
M
2
=70, D
2
=24, H
2
=8, W
2
=work completed
Substitute the values:
1
90×16×12
=
W
2
70×24×8
17280=
W
2
13440
W
2
=
17280
13440
=
1728
1344
=
9
7
So,
9
7
of the work is completed.
Work left:
Remaining Work=1−
9
7
=
9
2
1
=1.
Using the chain rule formula:
W
1
M
1
×D
1
×H
1
=
W
2
M
2
×D
2
×H
2
Where:
M
1
=90, D
1
=16, H
1
=12, W
1
=1
M
2
=70, D
2
=24, H
2
=8, W
2
=work completed
Substitute the values:
1
90×16×12
=
W
2
70×24×8
17280=
W
2
13440
W
2
=
17280
13440
=
1728
1344
=
9
7
So,
9
7
of the work is completed.
Work left:
Remaining Work=1−
9
7
=
9
2