Question
Sum of the first 30 terms of an arithmetic progression is 0. If the first term is -29, then find the sum of the 28th, 29th and 30th terms of this arithmetic progression.
Answer: Option A
:
A
Let the common difference of the arithmetic progression be 'd'.
Sum of first 30 terms of the arithmetic progression
=302×[2(−29)+(30−1)d]
Hence, 15(−58+29d) = 0
Hence, d=2
Sum of 28th, 29th and 30th term of this arithmetic progression
= 3(-29) + (27 + 28 +29) × 2 = 81
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:
A
Let the common difference of the arithmetic progression be 'd'.
Sum of first 30 terms of the arithmetic progression
=302×[2(−29)+(30−1)d]
Hence, 15(−58+29d) = 0
Hence, d=2
Sum of 28th, 29th and 30th term of this arithmetic progression
= 3(-29) + (27 + 28 +29) × 2 = 81
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