Q. 404.8( 10 Votes )

Sum of the first 14 terms of an AP is 1505 and its first term is 10. Find its 25th term.

Answer :

Here, first term = a = 10

Let the Common difference = d


Sum of first 14 terms = S14 = 1505


Now, Sum of n terms of this arithmetic series is given by:


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


S14 = [2(10) + (14 - 1)d] = 1505


7 × [20 + 13d] = 1505


[20 + 13d] = 215


13d = 195


d = 15


Now, nth term is given by:


an = a + (n - 1)d


a25 = 10 + (25 - 1)15


= 10 + (24 × 15)


= 10 + 360


= 370


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Champ Quiz | Arithmetic Progression34 mins
Champ Quiz | Arithmetic Progression30 mins
Lets Check Your Knowledge in A.P.49 mins
Arithmetic progression: Previous Year NTSE Questions34 mins
Quiz on Arithmetic Progression Quiz32 mins
Get to Know About Geometric Progression41 mins
NCERT | Solving Questions on Introduction of A.P42 mins
Become a Master of A.P. in 45 Minutes!!47 mins
Arithmetic Progression Tricks and QUIZ37 mins
Quiz | Group of Questions on General Term of an A.P49 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
view all courses