Carcass wrote:
In how many ways, 10 identical chocolates be distributed among 3 children such that each child gets at least 1 chocolate?
A. 36
B. 66
C. 72
D. 78
E. 84.
One approach is to
look for a patternSay the 3 children are A, B, C
We'll denote each outcome as follows:
# chocolates for A | # chocolates for B | # chocolates for C Number of outcomes in which child A receives exactly 1 chocolate1 | 1 | 8
1 | 2 | 7
1 | 3 | 6
1 | 4 | 5
1 | 5 | 4
1 | 6 | 3
1 | 7 | 2
1 | 8 | 1
8 outcomes
Number of outcomes in which child A receives exactly 2 chocolates2 | 1 | 7
2 | 2 | 6
2 | 3 | 5
2 | 4 | 4
2 | 5 | 3
2 | 6 | 2
2 | 7 | 1
7 outcomes
Number of outcomes in which child A receives exactly 3 chocolates3 | 1 | 6
3 | 2 | 5
3 | 3 | 4
3 | 4 | 3
3 | 5 | 2
3 | 6 | 1
6 outcomes
See the pattern?
So, the TOTAL number of outcomes =
8 +
7 +
6 +
5 +
4 +
3 +
2 +
1 =
36 Answer: A
Cheers,
Brent