Mathematics
Find the sum :
2 + 7 + 12 + 17 + ….. to 19 terms.
AP
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Answer
The above sequence is an A.P. with common difference = 12 - 7 = 5.
We know that,
Sum of n terms of an A.P. is given by,
∴ Sn = [2a + (n - 1)d]
⇒ S19 = [2(2) + (19 - 1)5]
= 9.5 [4 + (18)5]
= 9.5 [4 + 90]
= 9.5 (94)
= 893.
Hence, S19 = 893.
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