How many joists spaced 19 in. o.c. (on center) are required for a floor 418 in. long? (Add one joist for a starter.)
joists are required for a floor.
(Type a whole number.)

To determine the number of joists needed for a floor that is 418 inches long with joists spaced 19 inches on center, you can follow this simple calculation: first, you need to find out how many spaces of 19 inches fit into 418 inches.

Divide 418 by 19, which gives you approximately 22. Therefore, you would have 22 spaces. However, to find the number of joists, you add 1 (for the starter joist). This means you need 22 + 1 = 23 joists in total.

So, 23 joists are required for a floor.