A building code states that a set of stairs cannot rise more than 30 cm for each 75 cm of run. What is the maximum angle at which the stairs can rise? Draw a picture and round your answer to the nearest degree.

i think da answer is

d.square root of 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."