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.]
Asked
Active
Viewed 4,751 times
2 Answers
1
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, $$\binom{5+3-1}{3}=\binom{7}{3}=\frac{7\times 6\times 5}{1\times 2\times 3}=35$$

David
- 4,201
1
If I'm not mistaken, another solution (just to add flavor), would be:
$5\choose 1$ + $2$$5\choose 2$ + $5\choose 3$$=35$

Vincent
- 2,329