We have 8 pieces of strawberry candy and 7 pieces of pineapple candy. In how many ways can we distribute this candy to 4 kids?
I don't know Mellie, but
If there are 8 strawberry candies and each child gets at least one of them then that is (8+4-1)C8 = 11C8 = 165 ways
If there are 7 pineabpple candies and each child gets at least one of them then that is (7+4-1)C7 = 10C7=120
So if every child gets at least on of each then that would be 11C8*10C7 = 165*120 = 19800 ways
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NOW what about if one or more children get no pinapple lollies or no strawberry lollies or no lollies at all :/
If there are 8 strawberry candies and each child gets at least one of them then that is (8+4-1)C8 = 11C8 = 165 ways
If one child gets 0 strawbs then this can be done in (8+3-1)C8 = 10C8=45 ways
If two children gets 0 strawbs then this can be done in (8+2-1)C8 = 9C8=9 ways
If three children get 0 strawbs then this can be done in (8+1-1)C8=1 way (which makes sense because one child is getting all the strawb lollies.
So the number of ways that the strawberry lollies can be distributed is 165+45+9+1 = 220 ways
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If there are 7 pineapple candies and each child gets at least one of them then that is (7+4-1)C7 = 10C7=120
If one child gets 0 pineapple candies then this can be done in (7+3-1)C7 = 9C7= 36 ways
If two children gets 0 pineapple candies then this can be done in (7+2-1)C7 = 8C7=8 ways
If three children get 0 pineapple candies then this can be done in 1 way
So the number of ways that the pineapple candies can be distributed is 120+36+8+1 = 165 ways
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so the number of ways the lollies can be distributed is 220*165=36,300 ways
(some children might get none)
.
$$\ ${Use this formula for each set then multiply the sets}\\
\displaystyle \left( {\begin{array}{*{20}c} N + K - 1 \\ K-1 \\ \end{array}} \right)\; =\; distributions \\
\displaystyle \left( {\begin{array}{*{20}c} 8+4-1\\ 4-1 \\ \end{array}} \right)\; =\; 165 \\
\displaystyle \left( {\begin{array}{*{20}c} 7+4-1\\ 4-1 \\ \end{array}} \right)\; =\; 120 \\
\ 165 * 120\; =\; 19,800$$