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The sum of the first 12 terms of an A.P. is 900. If its first term is 20 then find the common difference and 12th term.
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The sum of the first 12 terms of an A.P. is 900. If its first term is 20 then find the common difference and 12th term.
cbse
class 10
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Sep 7
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Haren
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12/2 [2 × 20 + 11d] = 900
⇒ d = 10
Also a
12
= 20 + 11 × 10 = 130
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