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Question
In an AP Given a12 = 37, d = 3, find a and S12.
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Solution
Given that, a12 = 37, d = 3
As an = a + (n − 1)d,
a12 = a + (12 − 1)3
37 = a + 11d
37 = a + 11 × 3
37 = a + 33
a = 37 - 33
a = 4
`S_n = n/2 [a+a_n]`
`S_n = 12/2 [4+37]`
`S_n = 6(41)`
`S_n = 246`
Thus, a = 4 and S12 = 246
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