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

What is the sum of first 14 terms of the A.P. 12,15,18,21....?

A
144
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
114
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
441
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
414
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is C 441
First term of the given arithmetic series = 12
Second term of the given arithmetic series = 15
Third term of the given arithmetic series = 18
Fourth term of the given arithmetic series = 21
Now, Second term - First term = 15 - 12 = 3
Third term - Second term = 18 - 15 = 3
Therefore, common difference of the given arithmetic series is 3.
The number of terms of the given A. P. series (n) = 14
We know that the sum of first n terms of the Arithmetic Progress, whose first term = a and common difference = d is given by:
Sn=n2[2a+(n1)d]
S14=142[2×12+(141)×3]
S14=7[24+39]
S14=441

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Formula for Sum of N Terms of an AP
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon