[Math] How many combinations of three scoop cones are possibles

combinatoricselementary-set-theory

An ice cream shop sells ice creams in five possible flavours. How many combinations of three scoop cones are possibles?[Note:The repetition of flavours is allowed but the order in which the flavours are chosen does not matter.]

Best Answer

To calculate choosing $n$ numbers with replacement you use, $$\binom{n+m-1}{m}$$

where $n$ in the total numbers in the set, and m is how many numbers you want to choose.

So, $$\binom{5+3-1}{3}=\binom{7}{3}=\frac{7\times 6\times 5}{1\times 2\times 3}=35$$