CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

In the series 3, 9, 15, ...... what will be the 21st term?

A
117
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
121
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
123
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
129
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 123
Clearly, 3 + 6 = 9, 9 + 6 = 15,.....
So, the series is an A.P. in which a = 3 and d = 6.
Therefore 21st term = a + (21 - 1) d = a + 20d = 3 + 20 x 6 = 123.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Summation by Sigma Method
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon