# Find the expected value of choosing 3 balls among 8 (each balls has different value) [closed]

Let's say you have 8 balls in front of you, each of them contains a bank note (for example 1\$, 5\$, 10\$etc...). And let's say you can choose randomly 3 balls among the 8 (you don't know what's inside). How to compute the expected gain, in function of the value of each notes? As an example, let's say I have the following available notes: 0\$, 0\$, 0\$, 100\$, 100\$, 100\$, 200\$ and 500\$. The expected value should be 375$ (I did all the combinations by hand, but I want the formulae).

Thanks!

## closed as off-topic by Peter Flom♦Apr 5 at 13:55

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