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Find the sum of: 24 terms and n terms ...

Find the sum of:
24 terms and n terms of `2 (1)/(2) , 3 (1)/(3) , 4 (1)/(6) ,5 ,......,`

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To find the sum of the first 24 terms and the sum of the first n terms of the sequence given by the terms \(2 \frac{1}{2}, 3 \frac{1}{3}, 4 \frac{1}{6}, 5, \ldots\), we will first convert the mixed fractions into improper fractions, identify the pattern, and then use the formula for the sum of an arithmetic progression (AP). ### Step-by-step Solution: 1. **Convert Mixed Numbers to Improper Fractions:** - The first term is \(2 \frac{1}{2} = \frac{5}{2}\). - The second term is \(3 \frac{1}{3} = \frac{10}{3}\). - The third term is \(4 \frac{1}{6} = \frac{25}{6}\). - The fourth term is \(5 = \frac{5}{1}\). 2. **Identify the Terms:** - The terms are: - \(a_1 = \frac{5}{2}\) - \(a_2 = \frac{10}{3}\) - \(a_3 = \frac{25}{6}\) - \(a_4 = 5\) 3. **Calculate the Common Difference (d):** - To find the common difference \(d\), we calculate: \[ d = a_2 - a_1 = \frac{10}{3} - \frac{5}{2} \] - Finding a common denominator (which is 6): \[ d = \left(\frac{10 \times 2}{3 \times 2}\right) - \left(\frac{5 \times 3}{2 \times 3}\right) = \frac{20}{6} - \frac{15}{6} = \frac{5}{6} \] 4. **Use the Sum Formula for AP:** - The formula for the sum of the first \(n\) terms of an AP is: \[ S_n = \frac{n}{2} \left(2a + (n-1)d\right) \] - Here, \(a = \frac{5}{2}\), \(d = \frac{5}{6}\), and \(n = 24\). 5. **Plug in the Values:** - Calculate \(S_{24}\): \[ S_{24} = \frac{24}{2} \left(2 \cdot \frac{5}{2} + (24-1) \cdot \frac{5}{6}\right) \] - Simplifying: \[ S_{24} = 12 \left(5 + 23 \cdot \frac{5}{6}\right) \] - Calculate \(23 \cdot \frac{5}{6}\): \[ 23 \cdot \frac{5}{6} = \frac{115}{6} \] - Now, add: \[ 5 = \frac{30}{6} \quad \Rightarrow \quad 5 + \frac{115}{6} = \frac{30 + 115}{6} = \frac{145}{6} \] - Now, substitute back: \[ S_{24} = 12 \cdot \frac{145}{6} = \frac{1740}{6} = 290 \] 6. **Conclusion:** - Therefore, the sum of the first 24 terms is \(290\).
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