InterviewSolution
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InterviewSolution
| 1. |
The sum of even numbers between 1 and 31 is: |
| Answer» Let Sn = (2 + 4 + 6 + ... + 30). This is an A.P. in which a = 2, d = 2 and l = 30 Let the number of terms be n. Then, a + (n - 1)d = 30 2 + (n - 1) x 2 = 30 n = 15. Sn = n (a + l) = 15 x (2 + 30) = (15 x 16) = 240. 2 2 | |