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If the variance of the first 50 odd natu...

If the variance of the first 50 odd natural numbers is `V_(1)` and the variance of next 50 odd natural numbers is `V_(2)`, then `V_(1)+V_(2)` is equal to

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To solve the problem, we need to find the variances \( V_1 \) and \( V_2 \) of the first 50 odd natural numbers and the next 50 odd natural numbers respectively, and then compute \( V_1 + V_2 \). ### Step 1: Identify the first 50 odd natural numbers The first 50 odd natural numbers are: \[ 1, 3, 5, 7, \ldots, 99 \] ### Step 2: Calculate the mean of the first 50 odd natural numbers The mean \( \mu_1 \) can be calculated as: \[ \mu_1 = \frac{\text{Sum of the first 50 odd natural numbers}}{50} \] The sum of the first \( n \) odd natural numbers is given by \( n^2 \). Thus, for \( n = 50 \): \[ \text{Sum} = 50^2 = 2500 \] So, \[ \mu_1 = \frac{2500}{50} = 50 \] ### Step 3: Calculate the variance \( V_1 \) The variance \( V_1 \) is calculated using the formula: \[ V_1 = \frac{\sum (x_i^2)}{n} - \mu_1^2 \] Where \( x_i \) are the first 50 odd natural numbers. #### Step 3.1: Calculate \( \sum (x_i^2) \) We need to calculate: \[ \sum_{i=1}^{50} (2i - 1)^2 = \sum_{i=1}^{50} (4i^2 - 4i + 1) \] This can be broken down into: \[ 4\sum_{i=1}^{50} i^2 - 4\sum_{i=1}^{50} i + \sum_{i=1}^{50} 1 \] Using the formulas: - \( \sum_{i=1}^{n} i^2 = \frac{n(n+1)(2n+1)}{6} \) - \( \sum_{i=1}^{n} i = \frac{n(n+1)}{2} \) For \( n = 50 \): \[ \sum_{i=1}^{50} i^2 = \frac{50 \cdot 51 \cdot 101}{6} = 42925 \] \[ \sum_{i=1}^{50} i = \frac{50 \cdot 51}{2} = 1275 \] \[ \sum_{i=1}^{50} 1 = 50 \] Putting it all together: \[ \sum_{i=1}^{50} (2i - 1)^2 = 4 \cdot 42925 - 4 \cdot 1275 + 50 = 171700 - 5100 + 50 = 166650 \] #### Step 3.2: Substitute into the variance formula Now substituting back to find \( V_1 \): \[ V_1 = \frac{166650}{50} - 50^2 = 3333 - 2500 = 833 \] ### Step 4: Identify the next 50 odd natural numbers The next 50 odd natural numbers are: \[ 101, 103, 105, \ldots, 199 \] ### Step 5: Calculate the mean of the next 50 odd natural numbers The mean \( \mu_2 \) can be calculated as: \[ \mu_2 = \frac{\text{Sum of the next 50 odd natural numbers}}{50} \] The sum of these numbers is: \[ \text{Sum} = 101 + 103 + \ldots + 199 = 50^2 + 100 \cdot 50 = 2500 + 5000 = 7500 \] Thus, \[ \mu_2 = \frac{7500}{50} = 150 \] ### Step 6: Calculate the variance \( V_2 \) By the same reasoning as before, since the next 50 odd natural numbers are just the first 50 odd natural numbers shifted by 100, the variance \( V_2 \) will be the same as \( V_1 \): \[ V_2 = V_1 = 833 \] ### Step 7: Calculate \( V_1 + V_2 \) \[ V_1 + V_2 = 833 + 833 = 1666 \] Thus, the final answer is: \[ \boxed{1666} \]
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