Help I'm dying
Find the number of ways of placing 4 balls in 5 boxes if the balls are indistinguishable and the boxes are distinguishable.
First lay out the number of ways to distribute the 4 balls:
4 - 0 - 0 - 0 - 0
3 - 1 - 0 - 0 - 0
2 - 1 - 1 - 0 - 0
2 - 2 - 0 - 0 - 0
1 - 1 - 1 - 1 - 0
For the first case, there are \({5 \choose 1} = 5\) ways to choose the box for the 4, and the rest must be 0
For the second case, there are \({5 \choose 3} \times {2 \choose 1} = 20\) ways.
For the third case, there are \({5 \choose 1} \times {4 \choose 2} = 30\) cases
For the fourth case, there are \({5 \choose 2} = 10\) cases.
For, the final one, there are \({5 \choose 1} = 5\) ways.
So, in total there are \(5 + 5 + 10 + 20 + 30 = \color{brown}\boxed{70}\) ways.