If 20 Men can Build a Wall 56 Meters Long in 6 Days, What Length of a Similar Wall can be Built by 35 Men in 3 Days?

• If 20 men can build a wall 56 meters long in 6 days.

• Length of a similar wall built by 35 men in 3 days can be figure out in this way.

• Explanation

• Solution

Explanation

Three given entities here are

1. Men
2. Days
3. Length of Wall

To determine the relation here, let suppose length of wall built by 35 men in 3 days = y

Case I

Men           Length of Wall

20               56

35               y

• More men can build longer wall.
• Less men can build a wall but not much longer.

This clearly indicates that there is direct relation.

Direct/Indirect relation tells how the equation will be written.

20 : 35  ::  56 : y ________ (i)

Case II

Days           Length of Wall

6                 56

3                 y

• More days means more time to build longer wall.
• Less days means little time to build a wall.

This clearly indicates that there is direct relation.

Direct/Indirect relation tells how the equation will be written.

6 : 3  ::  56 : y ________ (ii)

By (i) and (ii)

20 : 35 :: 56 : y

  6 : 3

35 x 3 x 56 = 20 x 6 x y ________ (A)

After simplifying equation (A), we can easily figure out the value of y (y = 49)

To Find

Length of wall built by 35 men in 3 days = ?

Solution

Method I

Let suppose

Length of wall built by 35 men in 3 days = y

Men           Days           Length of Wall

20               6                 56

35               3                 y

Relation between men and length of wall & days and length of wall is direct so;

20 : 35 :: 56 : y

6 : 3

35 x 3 x 56 = 20 x 6 x y

5880 = 120y

y = 5880/120

y = 49 meters

Length of wall built by 35 men in 3 days = 49 meters answer

Method II

20 men can build a wall in 6 days = 56 meters

20 men can build a wall in 1 day = 56/6 meters

20 men can build a wall in 1 day = 9.333 meters

1 man can build a wall in 1 day = 9.333/20 meters

1 man can build a wall in 1 day = 0.467 meters

35 men can build a wall in 1 day = 0.467 x 35 meters

35 men can build a wall in 1 day = 16.333 meters

35 men can build a wall in 3 days = 16.333 x 3 meters

35 men can build a wall in 3 days = 49 meters

Length of wall built by 35 men in 3 days = 49 meters answer

Conclusion

If 20 men can build a wall 56 meters long in 6 days, then 49 meters length of a similar wall can be built by 35 men in 3 days.