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Question
If 3 men or 6 boys can finish a work in 20 days, how long will 4 men and 12 boys take to finish the same work?
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Solution
3 men = 6 boys
4 men = `6/3xx4` = 8
Total boys in second case :
= 4 men + 12 boys = 8 + 12 = 20 boys
6 boys can do a piece of work in 20 days
Then let 20 boys will do the same work in x days
∴ 6 : 20 : : 20 : x ........(More boys,less days)
⇒ 6 : 20 : : x : 20 ....(By inverse proportion)
x = `(20xx6)/20`
= 6 days
∴ They will do the work in 6 days
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