Answer :
nth term = 5n - 1
Put n=1, we get
1st term = 5-1 = 4
Hence sum of n terms = n(First term + nth term)/2
= n(4+5n - 1)/2
= n(5n +3)/2
Sum of 20 terms becomes, put n = 20
S20 = [20(5×20 +3)]/2
=10(103) = 1030
Rate this question :
How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Arithmetic Progression and 'nth' Term of AP55 mins
Sum of n Terms of AP56 mins
Introduction of Geometric Progression60 mins
Imp Qs Practice For Boards (AP)59 mins
Arithmetic Progression and 'nth' Term of AP55 minsSum of n Terms of AP56 minsIntroduction of Geometric Progression60 minsImp Qs Practice For Boards (AP)59 minsTry our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
view all courses
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
