At a lumber company, shelves are sold in 4 types of wood, 3 different widths and 3 different lengths. How many different types of shelves could be ordered?

36

Step-by-step explanation:

Pretty simple

Multiply the numbers of different type of wood by the different type of length by the different type of width which is 4x3x3 = 36

4 wood type A B C D

3 length type L1 L2 L3

3 width type 1 2 3

So for wood A we have, (L1, 1) (L1,2) (L1,3) (L2,1) (L2,2) (L2,3) (L3,1) (L3,2) (L3,3)

for wood B we have, (L1, 1) (L1,2) (L1,3) (L2,1) (L2,2) (L2,3) (L3,1) (L3,2) (L3,3)

for wood C we have, (L1, 1) (L1,2) (L1,3) (L2,1) (L2,2) (L2,3) (L3,1) (L3,2) (L3,3)

for wood D we have, (L1, 1) (L1,2) (L1,3) (L2,1) (L2,2) (L2,3) (L3,1) (L3,2) (L3,3) if we count the combinations together we will arrive at 36