Math Problems

Question 1

A stairway is 9’ 2” with 16 risers. What is the unit rise?

Answer 1

9’ x 12’ (per foot) = 108” + 2” = 110” divided by 16 (risers) = 6’ 7/8”

Question 2

A room is 12’ x 16’ with an 8’ ceiling. What is the square footage of gypsum boards needed?

Answer 2

640 = 12+12+16+16
56’ walls x 8’ ceiling = 448 sqft
12x16 = 192 sqft
192 + 448 = 640 sq ft

Question 3

How many full sheets of 4’ x 8’ plywood are needed for a rectangular subfloor that is 32’ x 72’ (do not count waste)

Answer 3

plywood 4 x 8 = 32 SF
32’ x 72’ = 2,304 divided by 32 = 72 sheets

Question 4

A supplier has given a quote of 0.42 cents per board foot over 12’ long. What is the cost of a 2’’ x 10” that is 20’ long?

Answer 4

2” x 10” x 20’ divided by 12” (per foot) = 33.33 board feet x 0.42 cents = $14.00

Question 5

How many 4’ x 12’ x 2” styrofoam sheets are required to protect the waterproofing membranes on a foundation 32’ x 60’ with a waterproofed height of 8’?

Answer 5

32+32+60+60 = 184 x 8’ (height) = 1,472 SF divided by 48 (4’x12’) = 31

Question 6

How many 12” x 8” x 16” blocks are there in one course of a 12’ long wall?

Answer 6

Brick / Block = W H L
12’ x 12”/ft divided by 16”/block = 9 blocks

Question 7

8’ x