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.
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
= 30/2*[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
= 30/2*[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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