2 men and 3 boys can do a piece of work in 10- days while 3 men and 2 boys can finish it in 8 days. number of days taken by 2 men and 1 boy to finsh it will be
Answers
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STEP 1: Form the equations:
2 men and 3 boys can do a piece of work in 10 days
⇒ 2M + 3B = 10D
.
3 men and 2 boys can finish it in 8 days:
⇒3M + 2B = 8D
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STEP 2: Find 1 man in term of boys:
Since the work is the same:
(2 x 10)
M + (3 x 10)B = (3 x 8)M + (2 x 8)B
.
20M + 30B = 24M + 16B
24M - 20M = 30B - 16B
4M = 14B
1M = 3.5B
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STEP 3: Find 2 men and 1 boy in term of boys:
2M + 1B = 2(3.5B) + 1B = 8B
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STEP 4: Find the number of days needed if there is only 1 boy:
2M + 3B = 10D
2(3.5B) + 3B = 10D
10B = 10D
1B = 10 x 10
1B = 100 days
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STEP 4: Find the number of days needed if there were 8 boys:
1B = 100 days
8B = 100 ÷ 8 = 12.5 days
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Answer: 2 men and 1 boy need 12.5 days to finish the work.
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