# 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? - Mathematics

Sum

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?

#### 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

Concept: Time and Work
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#### APPEARS IN

Selina Concise Mathematics Class 8 ICSE
Chapter 10 Direct and Inverse Variations
Exercise 10 (C) | Q 12 | Page 126