If 7th and 13th terms of an A.P. be 34 and 64 respectively, then its 18th term is
A. 87
B. 88
C. 89
D. 90
Answer: Option C
Solution(By Examveda Team)
7th term (a7) = a + 6d = 3413th term (a13) = a + 12d = 64
Subtracting, 6d = 30 ⇒ d = 5
and a + 12 x 5 = 64
⇒ a + 60 = 64
⇒ a = 64 – 60 = 4
18th term (a18)
= a + 17d
= 4 + 17 x 5
= 4 + 85
= 89
Related Questions on Progressions
Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.
A. 5
B. 6
C. 4
D. 3
E. 7
The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is
A. 600
B. 765
C. 640
D. 680
E. 690
Join The Discussion