We have to find sum of first 20 terms, so we put n as 20 in the formula for sum of n terms, i.e. \[{S_n} = \dfrac{n}{2}(2a + (n - 1)d)\]. So, the sum of the first 20 terms of the series formed by common terms of two given series is 4020. So, the correct answer is “Option A”.
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Answer:
We have to find sum of first 20 terms, so we put n as 20 in the formula for sum of n terms, i.e. \[{S_n} = \dfrac{n}{2}(2a + (n - 1)d)\]. So, the sum of the first 20 terms of the series formed by common terms of two given series is 4020. So, the correct answer is “Option A”.
Step-by-step explanation:
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