18 men or 36 boys working 6 hours a day can plough a field in 24 days. in how many days will 24 men and 24 boys working 9 hours a day plough the same field ?
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Answered by
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18 men 6 hrs a day take 24 days
- That means 1 man covers (1/18 ×1/6 × 1/24 =1/2592) in 1 hour
36 boys 6 hours take 24 days
- That means 1 boy covers (1/36 × 1/6 × 1/24) = 1/5184 in 1 hour
So how long will 24 men and 24 boys take working 9 hours a day:
24 men 9hours/day will cover = 24 × 9 × 1/2592 = 216/2592 of the field
24boys 9hours/day will cover = 24 × 9 × 1/5184 = 216/5184 of the field
Add the two fractions to find the size of field covered in 1 day by the 24 men and the 24 boys
--> 216/2592 + 216/5184 = (432 + 216)/5184 = 648/5184
If 648/5184 of the field is covered in 1 day
Then 5184/5184 will be covered in 5184/184 ×1/( 648/)5184
= 5184/648
= 8 days
That means 24 of the men and 24 of the boys working together, 9 hours a day will take 8 hours to complete the same field
- That means 1 man covers (1/18 ×1/6 × 1/24 =1/2592) in 1 hour
36 boys 6 hours take 24 days
- That means 1 boy covers (1/36 × 1/6 × 1/24) = 1/5184 in 1 hour
So how long will 24 men and 24 boys take working 9 hours a day:
24 men 9hours/day will cover = 24 × 9 × 1/2592 = 216/2592 of the field
24boys 9hours/day will cover = 24 × 9 × 1/5184 = 216/5184 of the field
Add the two fractions to find the size of field covered in 1 day by the 24 men and the 24 boys
--> 216/2592 + 216/5184 = (432 + 216)/5184 = 648/5184
If 648/5184 of the field is covered in 1 day
Then 5184/5184 will be covered in 5184/184 ×1/( 648/)5184
= 5184/648
= 8 days
That means 24 of the men and 24 of the boys working together, 9 hours a day will take 8 hours to complete the same field
Answered by
1
Answer:
step by step explanation
18m=36b
=》m/b=2/1
we know
total work=men×efficiency ×hrs×days
=18×2×6×24
•°•tw=(24m+24b)×9hrs×Days
18×2×6×24=(24×2+24×1)×9×24×D
=》D=18×2×6×24/((48+24)×9×24)
D=8days
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