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Question
Find the A.P. whose nth term is 7 – 3K. Also find the 20th term.
Solution
Tn = 7 – 3n
Giving values 1, 2, 3, 4, … to n, we get
T1 = 7 – 3 x 1 = 7 – 3 = 4
T2 = 7 – 3 x 2 = 7 – 6 = 1
T3 = 7 – 3 x 3 = 7 – 9 = -2
T4 = 7 – 3 x 4 = 7 – 12 = -5
T20 = 7 – 3 x 20 = 7 – 60 = -53
A.P. is 4, 1, -2, -5, …
20th term = -53
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