Q. 394.7( 6 Votes )

The 17th te

Answer :

Let a and d be the first term and common difference of the AP Given: a17 = 2 × a8 + 5

a11 = 43


To find: nth term = an


Consider a11 = 43


a + (11 - 1)d = 43


a + 10d = 43 ………….. (1)


Consider a17 = 2 × a8 + 5


a + (17 - 1)d = 2[a + (8 - 1)d] + 5


a + 16d = 2a + 14d + 5


- a + 2d = 5 ……………….(2)


Adding equation (1) and equation (2), we get


12d = 48


d = 4


from equation (1), we get,


a = 43 - 10d


= 43 - 40


= 3


Now, nth term is given by:


an = a + (n - 1)d


an = 3 + (n - 1)4


an = 4n - 1


Therefore, nth term is given by (4n - 1).

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 APArithmetic Progression and 'nth' Term of APArithmetic Progression and 'nth' Term of AP55 mins
Imp Qs Practice For Boards (AP)Imp Qs Practice For Boards (AP)Imp Qs Practice For Boards (AP)59 mins
Sum of n Terms of APSum of n Terms of APSum of n Terms of AP56 mins
Introduction of Geometric ProgressionIntroduction of Geometric ProgressionIntroduction of Geometric Progression60 mins
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