Question

I'LL GIVE BRANLY!!!!!

How many 3-coin combinations exist if we can choose from nickels, dimes, quarters, and half-dollars?
20
4!
4
12

Answer 1

20

Explanation:

If the order matters, we can use the product rule to show each of the
`20` coins can be chosen in
`5` ways, for a total of
`5^{20` ways, assuming you have enough of each type of coins.

If the order does not matter (which in the case it probably does not) you have to use an r-combination. The formula is
`C(n+r-1,r)`. Here
`n=5` and
`r=20`. So we get
`C(24,20)`.

Answer 2

12

Explanation: