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

# The series of natural numbers is divided into groups (1),(2,3,4),(3,4,5,6,7),(4,5,6,7,8,9,10),... Find the sum of the numbers in nth group.

A
[n+1]2
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
B
[n1]2
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
C
[2n1]2
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
[2n+1]2
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
Open in App
Solution

## The correct option is B [2n−1]2 (1),(2,3,4),(3,4,5,6,7),(4,5,6,7,8,9,10),...nth group contains 2n−1 terms which are in A.P. of common difference 1 and first term of successive groups are 1,2,3.... and hence of nth group is n. Sum of terms of nth group =2n−12[2.n+(2n−1−1).1]=2n−12[4n−2]=[2n−1]2Hence, option C.

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Formula for Sum of N Terms of an AP
MATHEMATICS
Watch in App
Join BYJU'S Learning Program