wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Question 12
If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term will be

A) 7
B) 11
C) 18
D) 0

Open in App
Solution

According to the question,
7a7=11a11
7[a+(71)d]=11[a+(111)d] [an=a+(n1)d]
7(a+6d)=11(a+10d)
7a+42d=11a+110d
4a+68d=0
2(2a+34d)=0 [20]
2a+34d=0
a+17d=0(i)
18th term of the AP,
a18=a+(181)d
=a+17d=0 [from eq.(i)]

flag
Suggest Corrections
thumbs-up
7
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon