23. 3
The eyepiece of a refracting telescope has a focal
length of 90cm. The distance between objective and
eyepiece is 1.8m and the final image is at infinity. What
is the angular magnification of the telescope? [2072'C'1
[Ans: 1]​

can you rephrase the question ? it is unclear : -)

step-by-step explanation:

i will with my problems and all the other things that need to   be on by the way

step-by-step explanation:

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."