   # 40 men can build a wall 20m high in 15 days. How many men required to build a similar wall 50 m high in 3 days?

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40 men can build a wall 20m high in 15 days. How many men required to build a similar wall 50 m high in 3 days? posted Oct 6, 2016

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40 men can build 20m high wall in 15 days
=> 1 men can build 20m high wall in 15*40 days
=> 1 men can build 1m high wall in 15*40/20 i.e. 30 days
=> 30 days 1m high wall requires 1 men
=> 30 days 50m high wall requires 1*50 men
=> 3 days 50m high wall required 1*50*10 men

500 Men required answer Oct 7, 2016
exactly correct answer 500men require to build 50 m hight wall in 3 days
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500 men is the correct answer.

The answer can be arrived at by increasing the number of men according to the following ratios:
40 men*(50m/20m)*(15days/3days) = 40men*2.5*5 = 500men answer Oct 8, 2016

First convert into meters per day/man: 20*15 = 300 meters per day/40 men = 7.5 meters per day/man
Then answer the question by using the new parameters: (50 meters)(3 days) = 150 meters per day/7.5 meters per day/man = meters per day canceling out leaving: 20 men are the new requirement.

Correction:

500 men is the correct answer.

The answer can be arrived at by increasing the number of men according to the following ratios:
40 men*(50m/20m)*(15days/3days) = 40men*2.5*5 = 500men

BTW: a thank you to those that provided the correct answer. Learning from mistakes allows a person to try different solutions.
And by being provided with the correct answer you can work the problem backwards, similar to reverse engineering. answer Oct 6, 2016

500 members required answer Oct 7, 2016

1.- 40 men build a wall 20 mts high in 15 days
2.- 40 men will build a wall 50 mts high in 15 x 50/20 ( 37,5 days)
3.- X men will build a wall 50 mts high in 37,5 / 12,5 ( 3 days)
Then the number of men will be : 40 x 12,5 = 500 men answer Oct 19, 2016 by anonymous

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