One of the most important and exam oriented question from Chapter name- Arithmetic Progression
Class 10th
Chapter number- 9
Exercise :- 9.6
This type of question has been asked in previous years exams.
In this question we have been given an arithmetic progression. And we have to find out sum of first 11th terms of this progression.
CBSE DHANPAT RAI publication
CBSE Mathematics Class 10th
Question 11(i)
Given A.P. has first term(a) = 2,
Common difference(d) = 6 − 2 = 4
and number of terms(n) = 11.
We know sum of n terms of an A.P. is given by, Sn = n[2a + (n − 1)d] / 2.
S11 = 11[2(2) + (11 − 1)4]/2
= 11[4 + 40]/2
= 11 × 22 = 242
Hence, the sum of first 11 terms of the given A.P. is 242.