The sum of first q terms an A.P is 162 . The ratio of its 6th term and 13th term is 1:2. Find the first and 15th term of the A.P.
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ratio = (a+5d) / (a+ 9d) = 1/2
=> a + d = 0
=>a = -d
sum of 9 terms = 162
9/2 * (2a + 8 d) = 162
6d = 36
d = 6
a = -6
first term = -6
t15 = -6 + 14*6 = 78
=> a + d = 0
=>a = -d
sum of 9 terms = 162
9/2 * (2a + 8 d) = 162
6d = 36
d = 6
a = -6
first term = -6
t15 = -6 + 14*6 = 78
jivishaeratkar21:
but here is no mentioned that sum of 9th term is 162
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