In how many ways 8 stones of different colours be arranged on a ring? ...
Arranging 8 stones on a ring:
To find the number of ways to arrange 8 stones of different colors on a ring, we can use the concept of circular permutations. Circular permutations are arrangements where the order of objects matters, but the starting point is not fixed.
The number of ways to arrange n objects in a circle is given by (n-1)!. In this case, we have 8 stones, so the number of arrangements is (8-1)! = 7!.
Therefore, there are 7! = 5040 ways to arrange 8 stones of different colors on a ring.
Arranging red and yellow beads separately:
To find the number of arrangements where the red and yellow beads are separated, we can consider them as a single unit. Let's call this unit "RY".
Now, we have 7 objects to arrange on the ring - RY, plus 6 other stones. The number of arrangements of these 7 objects can be found using circular permutations, which is (7-1)! = 6!.
But within the RY unit, the red and yellow beads can be arranged in 2! = 2 ways.
Therefore, the number of arrangements where the red and yellow beads are separated is 6! * 2 = 720.
Explanation:
1. Arranging 8 stones on a ring:
- To find the number of ways to arrange 8 stones of different colors on a ring, we use the concept of circular permutations.
- Circular permutations consider the order of objects but not the starting point.
- The formula for circular permutations is (n-1)!, where n is the number of objects.
- In this case, we have 8 stones, so the number of arrangements is (8-1)! = 7! = 5040.
2. Arranging red and yellow beads separately:
- To find the number of arrangements where the red and yellow beads are separated, we consider them as a single unit called RY.
- Now, we have 7 objects to arrange on the ring - RY and 6 other stones.
- The number of arrangements of these 7 objects can be found using circular permutations, which is (7-1)! = 6! = 720.
- But within the RY unit, the red and yellow beads can be arranged in 2! = 2 ways.
- Therefore, the number of arrangements where the red and yellow beads are separated is 6! * 2 = 720.
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