Answer :

Let a be the first term and d be the common difference.

Given: a4 + a8 = 24


and a6 + a10 = 44


To find: S10


Now, Consider a4 + a8 = 24


a + 3d + a + 7d= 24


2a + 10d = 24 ………….(1)


Consider a6 + a10 = 44


a + 5d + a + 9d = 44


2a + 14d = 44 ………..(2)


Subtracting equation (1) from equation (2), we get,


4d = 20


d = 5


Common difference = d = 5


Thus from equation (1), we get,


a = - 13


Now, Sum of first n terms of an AP is


Sn = [2a + (n - 1)d]


Sum of first 10 terms is given by:


S10 = [2(-13) + (10 - 1)(5)]


= 5 × [ - 26 + 45]


= 5 × 19


= 95


S10 = 95


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses