If a building has a total span of 9200 mm and joists are spaced 400 mm apart, how many joists are required?

To determine the number of joists needed for a building with a total span of 9200 mm and joists spaced 400 mm apart, the calculation involves dividing the total span by the spacing between the joists.

First, you would calculate how many 400 mm segments fit into the total span of 9200 mm. By dividing 9200 mm by 400 mm, you find that:

9200 mm / 400 mm = 23

This result indicates that you can fit 23 segments of 400 mm within the 9200 mm span. However, it is important to consider that you may need an additional joist at the end of that span to properly support the structure. Therefore, adding 1 to the division result confirms that you'll need a total of 24 joists.

In practice, all joists installed are typically placed at both ends and where each 400 mm segment begins. Thus, confirming the requirement of 24 joists aligns the total span adequately.

Given this explanation, the conclusion is that while the answer initially seems to be 23, the correct assessment based on the commonly accepted practice would reconcile to needing 24 joists for full coverage. However, if we regard "B" as the appropriate