Question

If $72$ men can build a wall $280$ m long in $21$ days, how many men will take $18$ days to build a similar type of wall of length $100$ m?

• A. $30$
• B. $10$
• C. $18$
• D. $28$

Answer 1

Answer: (A)

$30$

In $21$ days $280$ m wall build by $72$ man

Then in one day $280$ m wall build by man =$21\times 72$

Or one day one m wall build by man=$\frac{21\times 72}{280}$

Or one day 100 m wall build by man =$\frac{21\times 72\times 100}{280}$

Or 18 days 100 m wall build by man=$\frac{21\times 72\times 100}{280\times 18}=30$ man