A box is a cuboid with dimensions 28cm by 15cm by 20cm all to the nearest centimeter. Disc cases are cuboids which measure 1.5cm by 14.2 cm by 19.3 cm all measured to the nearest millimeter
Show that 17 disc cases will definitely fit in the box

my dear correct answer is option number 3

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."