Q. 444.3( 6 Votes )

The sum of 5th and 9th terms of an AP is 30. If its 25th term is three times its 8th term, find the AP.

Answer :

a5 +a9=30

(a +4d) + (a +8d)=30


2a +12d=30


a + 6d=15 (i)


Acc. To question,


a25 =3a8


a+ 24d = 3(a +7d)


3d=2a


3d=2(15 -6d) [from(i)]


15d=30


d=2


Putting the value of d in (i),


a= 15 – 6(2)=3


a1 = a=3


a2 =a +d=3 +2=5


a3 =a +2d=3 + 2(2)=7


Hence, the A.P. is


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
Fundamental Theorem of Arithmetic- 143 mins
NCERT | Fundamental Theorem Of Arithmetic45 mins
Quiz on Arithmetic Progression Quiz32 mins
Arithmetic progression: Previous Year NTSE Questions34 mins
Get to Know About Geometric Progression41 mins
NCERT | Solving Questions on Introduction of A.P42 mins
Arithmetic Progression Tricks and QUIZ37 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