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Question
An A.P. consists of 60 terms, If the first and the last terms be 7 and 125 respectively, find the 31st term.
Solution
For a given A.P.,
Number of terms, n = 60
First term, a = 7
Last term, l = 125
`\implies` t60 = 125
`\implies` a + 59d = 125
`\implies` 7 + 59d = 125
`\implies` 59d = 118
`\implies` d = 2
Hence, t31 = a + 30d
= 7 + 30(2)
= 7 + 60
= 67
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