Question

the sum of first q terms of an A.P. is 162. the ratio of its 6th term to its 13th term is 1:2 . find the first and 15th term of an A.P. pls. do the full solution each and every line

Answer 1

sum of first q terms of an A.P. is 162

let first term be  'a'

common difference is 'd'

a+5d/a+12d =1/2

2a +10d = a + 12d

a=2d ------> 1

sum q = q/2(2a+(q-1)d)

162*2= q(2a+(q-1)d)

324 = 2aq + (q^2)d-qd

substitute 1

324 = 2aq +(q^2)*2a-q*2a

324 = (q +(q^2)-q)*2a

162 = (q +(q^2)-q)*a

162 =  a(q^2)

Answer 2

Answer:

Step-by-step explanation:

I think question is little bit incorrect

There is 9 instead of q

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