A furniture manufacturer offers bookcases in 5 different sizes and 3 different colors. If every color is available in every size, then the total number of different bookcases is

we are given

A furniture manufacturer offers bookcases in 5 different sizes

so, number of bookcases of different size = 5

A furniture manufacturer offers bookcases in 3 different colors

so, number of bookcases of different colors = 3

since, every color is available in every size

so,

total number of different bookcases = (number of bookcases of different size) * (number of bookcases of different colors)

now, we can plug values

and we get

total number of different bookcases=5*3

So, total number of different bookcases is 15 ... Answer