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A total of 6 Boys and 6 girls are to sit...

A total of 6 Boys and 6 girls are to sit in a row alternatively and in a circle. Let m be the number of arrangements in the row and n be the number of arrangements in the circle. If `k=(m)/(10_(n))`, then the value of k is

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To solve the problem, we need to calculate the number of arrangements of 6 boys and 6 girls sitting alternatively in a row and in a circle. We will denote the number of arrangements in a row as \( m \) and in a circle as \( n \). Finally, we will find the value of \( k = \frac{m}{10n} \). ### Step 1: Calculate \( m \) (Arrangements in a Row) 1. **Arrangement in a Row**: Since the boys and girls must sit alternately, we can start with either a boy or a girl. - If we start with a boy, the arrangement will be: B G B G B G B G B G B G. - If we start with a girl, the arrangement will be: G B G B G B G B G B G B. 2. **Calculating Arrangements**: - There are 6 boys and 6 girls. The number of ways to arrange the boys is \( 6! \) and the number of ways to arrange the girls is also \( 6! \). - Since we can start with either a boy or a girl, we multiply by 2. Therefore, the total number of arrangements in a row is: \[ m = 2 \times 6! \times 6! \] ### Step 2: Calculate \( n \) (Arrangements in a Circle) 1. **Arrangement in a Circle**: In circular arrangements, we fix one person to avoid counting rotations as different arrangements. We can fix one boy in one position. 2. **Calculating Arrangements**: - After fixing one boy, we have 5 remaining boys and 6 girls to arrange. - The arrangement will be: B G B G B G B G B G B G. - The number of ways to arrange the remaining 5 boys in a circle is \( (6-1)! = 5! \). - The number of ways to arrange the 6 girls is \( 6! \). Therefore, the total number of arrangements in a circle is: \[ n = 5! \times 6! \] ### Step 3: Calculate \( k \) Now, we can substitute \( m \) and \( n \) into the formula for \( k \): \[ k = \frac{m}{10n} = \frac{2 \times 6! \times 6!}{10 \times 5! \times 6!} \] ### Step 4: Simplify \( k \) 1. Cancel \( 6! \) from the numerator and denominator: \[ k = \frac{2 \times 6!}{10 \times 5!} \] 2. Recall that \( 6! = 6 \times 5! \): \[ k = \frac{2 \times 6 \times 5!}{10 \times 5!} \] 3. Cancel \( 5! \): \[ k = \frac{2 \times 6}{10} = \frac{12}{10} = \frac{6}{5} \] 4. Convert to decimal: \[ k = 1.2 \] ### Final Answer: The value of \( k \) is \( \frac{6}{5} \) or \( 1.2 \). ---
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