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 ?​

Answer 1

Answer:

The work can be completed in 20 days by 3 men or 6 boys.

Hence the capacity of 3 men = the capacity of 6 boys.

Hence if 4 men and 12 boys do the work together, than it is equivalent to,

4 + 6 = 10 men

Now the work quantum = 3 *20 = 60

Hence if now equivalent to 10 men are doing the work, then

No. of days = 60/10 = 6

$\:$

Answer 2

3 men = 6 boys

4 men = x 4 = 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 = (20 × 6)/20

= 6 days

∴ They will do the work in 6 days

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