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The 8th term of an A.P is equal to three times its third term.If its 6th term is 22,find the A.P
Given that t8 = 3t3
a + 7d = 3(a + 2d)
ie , a + 7d - 3a - 6d = 0
ie , -2a + d = 0 ----(i)
t6 = 22 
a + 5d = 22 -------(ii)
(ii) *2 gives 2a + 10d = 44 ------(iii)
(i) + (iii) gives 11d = 44
implies  d = 44 / 11 = 4
from (ii) , a = 22 - 5d
                  = 22 - 5*4
                  =22 - 20 = 2
Hence the required A.P is 2 , 6 , 10 , 14 , ---,  --- , ---


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