Question

In the year 2535, astronauts Milky and Way are blasting around the solar system. If they could decide to visit 5 of the 9 planet, how many different selections could they make?

Answer 1

do you know ""n choose k"": eg \(\\^nC_k \) or \(\left(\begin{matrix}n \\ k\end{matrix}\right) \)?

if you don't, you can draw a diagram and figure it out.

Answer 2

what

Answer 3

eg nCk or (nk)

Answer 4

idk what that is