If the 7th and 13th terms of an AP are 34 and 64, then its 18th term is ___.
A
87
No worries! Weāve got your back. Try BYJUāS free classes today!
B
88
No worries! Weāve got your back. Try BYJUāS free classes today!
C
89
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
90
No worries! Weāve got your back. Try BYJUāS free classes today!
Open in App
Solution
The correct option is C 89 The nth term of an AP of first term a and common difference d is an=a+(n−1)d.⇒a7=a+6d=34−−−(1)a13=a+12d=64−−−(2)(2)−(1)⇒6d=30⇒d=5Substituting d = 5 in (1), we get a=4.∴a18=a+17d=4+(17)5=89