Nine gifts, three of which are identical and the rest are distinct, are distributed among five people without restrictions on the number of gifts a person can have. By first considering the number of ways to distribute the distinct gifts or otherwise, find the number of way that the nine gifts can be distributed.
It won't just hand you the answer — it asks where you're stuck.How the checker works
Worked solution
6
1. Calculate the number of ways to distribute the 6 distinct gifts.
The number of distinct gifts is .
Since there are no restrictions, each of the distinct gifts can be given to any of the people.
Number of ways to distribute the distinct gifts = .
2. Calculate the number of ways to distribute the 3 identical gifts.
Since the gifts are identical, we only care about how many gifts each person receives. We can consider the possible groupings:
- All 3 gifts to 1 person: Choose person out of to receive all of them. This gives ways.
- 2 gifts to 1 person, 1 gift to another: Choose person to receive gifts ( ways), and of the remaining people to receive gift ( ways). This gives ways.
- 1 gift each to 3 different people: Choose people out of to receive gift each. This gives ways.
Total number of ways to distribute the identical gifts = .
(Alternatively, using the 'stars and bars' combinations with repetition formula: .)
3. Calculate the overall total number of ways to distribute all the gifts.
By the multiplication principle, the distinct and identical gifts can be distributed independently.
Total number of ways = .
AI analysis — may contain mistakes.
Worked this one out on paper? Snap your steps and Gigle's AI math checker will circle the step where it went wrong.
More questions on this topic
- 1A personality test assesses 32 key traits. These 32 traits are grouped into 4 domains - Cognition, Influence, Rapport an…
- 2An amateur music composer is arranging a sequence of four musical notes followed by three beats. There are 7 possible no…
- 3Kelly has a box of spherical beads labelled with the 26 letters from A to Z, all of which have the same size. For each l…
- 4为弘扬我国古代的“六艺”文化,某夏令营主办单位计划利用暑期开设“礼”“乐”“射”“御”“书”“数”六门体验课程,每周一门,连续开设六周,则 A. 某学生从中选三门,共有种选法 B. 课程“射”“御”排在不…
- 5把10个苹果分成三堆,要求每堆至少1个,至多5个,则不同的分法共有( ) A. 4种 B. 5种 C. 6种 D. 7种