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A family consists of a grandfather, 5 so...

A family consists of a grandfather, 5 sons and daughters and 8 grand child. They are to be seated in a row for dinner. The grand children wish to occupy the 4 seats at each end and the grandfather refuses to have a grandchild on either side of him. In how many ways can the family be made to sit?

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To solve the problem, we need to arrange a family consisting of a grandfather, 5 sons and daughters, and 8 grandchildren in a row for dinner, with specific seating restrictions. Let's break down the solution step by step. ### Step 1: Determine the total number of family members The family consists of: - 1 Grandfather - 5 Sons and Daughters - 8 Grandchildren Total family members = 1 + 5 + 8 = 14 ### Step 2: Identify seating restrictions - The grandchildren wish to occupy the 4 seats at each end of the table. - The grandfather refuses to have a grandchild on either side of him. ### Step 3: Arrange the grandchildren Since the grandchildren occupy the 4 seats at each end, we have: - 4 seats on the left end - 4 seats on the right end The total number of grandchildren is 8, and we need to choose 4 for the left end and 4 for the right end. The number of ways to choose 4 grandchildren from 8 for the left end is given by the combination formula: \[ \text{Ways to choose 4 from 8} = \binom{8}{4} \] After choosing the grandchildren, we can arrange them in the 4 seats at each end. The number of ways to arrange 4 grandchildren in 4 seats is: \[ 4! \text{ (for left end)} \times 4! \text{ (for right end)} \] ### Step 4: Arrange the grandfather and the sons and daughters Now, we have 6 remaining seats in the middle (since 4 on the left and 4 on the right are occupied by grandchildren). The grandfather must sit in one of these 6 seats, and he cannot have a grandchild on either side of him. This means that the grandfather can only sit between the sons and daughters. Since there are 5 sons and daughters, they create 4 gaps between them where the grandfather can sit. The number of ways to choose a gap for the grandfather is: \[ 4 \text{ (gaps)} \] ### Step 5: Arrange the sons and daughters The remaining 5 sons and daughters can be arranged in the remaining 5 seats. The number of ways to arrange them is: \[ 5! \] ### Step 6: Calculate the total arrangements Now, we can combine all the arrangements: 1. Choose and arrange grandchildren: \[ \binom{8}{4} \times 4! \times 4! \] 2. Choose a gap for the grandfather: \[ 4 \] 3. Arrange the sons and daughters: \[ 5! \] Putting it all together, the total number of arrangements is: \[ \text{Total arrangements} = \binom{8}{4} \times 4! \times 4! \times 4 \times 5! \] ### Final Calculation Calculating each component: - \(\binom{8}{4} = 70\) - \(4! = 24\) - \(5! = 120\) Now substituting these values: \[ \text{Total arrangements} = 70 \times 24 \times 24 \times 4 \times 120 \] Calculating this gives: \[ = 70 \times 576 \times 480 \] Thus, the final answer is: \[ \text{Total arrangements} = 480 \times 8! \] ### Conclusion Hence, the required number of ways the family can be seated is: \[ \text{Required number of ways} = 480 \times 8! \]

To solve the problem, we need to arrange a family consisting of a grandfather, 5 sons and daughters, and 8 grandchildren in a row for dinner, with specific seating restrictions. Let's break down the solution step by step. ### Step 1: Determine the total number of family members The family consists of: - 1 Grandfather - 5 Sons and Daughters - 8 Grandchildren ...
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