[amp_mcq option1=”300 to 350 mm” option2=”400 to 450 mm” option3=”500 to 550 mm” option4=”600 to 650 mm” correct=”option3″]<\/p>\n
The correct answer is: C. 500 to 550 mm.<\/p>\n
The sum of the tread and rise of a stair must lie between 500 and 550 mm. This is to ensure that the stair is comfortable and safe to use. If the tread is too small, it will be difficult to take a step and you may trip. If the rise is too high, it will be difficult to lift your leg and you may also trip. The ideal range for the sum of the tread and rise is 500 to 550 mm, as this allows for a comfortable and safe walking experience.<\/p>\n
Option A is incorrect because the sum of the tread and rise must be greater than 300 mm. This is to ensure that the stair is not too steep and you can comfortably walk up and down it.<\/p>\n
Option B is incorrect because the sum of the tread and rise must be less than 650 mm. This is to ensure that the stair is not too shallow and you can comfortably walk up and down it.<\/p>\n
Option D is incorrect because the sum of the tread and rise must be between 500 and 550 mm. This is to ensure that the stair is comfortable and safe to use.<\/p>\n","protected":false},"excerpt":{"rendered":"
[amp_mcq option1=”300 to 350 mm” option2=”400 to 450 mm” option3=”500 to 550 mm” option4=”600 to 650 mm” correct=”option3″]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[643],"tags":[],"class_list":["post-6089","post","type-post","status-publish","format-standard","hentry","category-building-construction","no-featured-image-padding"],"yoast_head":"\n