Explanation:

To check the size of a brick by keeping the number of bricks side by side, we need to apply a basic formula. The formula is:

Length of Brick = Total Length of Bricks / Number of Bricks

Here, we are given that the number of bricks to be kept side by side to check the size is 20. Therefore, we can apply the above formula as follows:

Length of Brick = Total Length of Bricks / 20

Now, we need to find out the total length of the bricks. This information is not given in the question. Therefore, we cannot find out the exact length of the brick. However, we can make an assumption based on the standard size of a brick.

The standard size of a brick is 190 mm × 90 mm × 90 mm. Therefore, the total length of 20 bricks kept side by side will be:

Total Length of Bricks = 20 × 190 mm = 3800 mm

Now, we can substitute this value in the formula to find out the length of the brick:

Length of Brick = 3800 mm / 20 = 190 mm

Therefore, the length of the brick is 190 mm.

Conclusion:

To check the size of a brick by keeping the number of bricks side by side, we need to use the formula Length of Brick = Total Length of Bricks / Number of Bricks. Based on the standard size of a brick, we can assume the total length of the bricks to find out the length of the brick. In this question, the number of bricks to be kept side by side is 20, and the length of the brick is found to be 190 mm. Therefore, the correct answer is option B.

According to BIS code IS-1077