the 17th term of an A.P is 5 more than twice its 8th term. if the 11th term of the A.P is 43 find the nth term
Given
17th term =2( 8th term) + 5
a+(17-1)d = 2(a+(8-1)d )+5
a+16d =2a+14d+5
-a+2d=5 ...(1)
Also given
11th term = 43
a+(11-1) d=43
a+ 10d =43 ...(2)
(1)+(2), 12d = 48==>d=4
(1)==? -a+8 = 5
-a = -3
a=3
So, a=3 and d=4;
nth term = a+(n-1)d = 3+(n-1)4 = 3+4n-4=4n-1