Question

The sum of 2nd and 7th term of an a.p is 30 . if it's 15th term is twice it's 8th term,fimd the a.p

Answer 1

Here is your solution

Given:-

t2+t7=30
=>a+d+a+6d=30
=>2a+7d=30..................... (1)

A/q
15th term=2×8th term-1
=>a+14d=2×(a+7d)
=>a+14d=2a+14d
=>14d-14d=2a-a
=>0=a

Putting the value of a in equation (1)

2a×7d=30
2×0+7d=30
2×0+7d=30
7d=30
7d=30
d=30/7

A.p are a,a+d,a+2d,a+3d,a+4d

=>A.p are 0,30/7,60/7,90/7

HOPE IT HELPS YOU

Answer 2

$\underline{\bold{Given:-}}$

$a_{2} + a_{7} = 30 \\ \\ a_{15} = 2 \times a_{8}$

$\underline{\bold{Solution:-}}$

The solution is given in the attachment.

$\underline{\bold{A.P :-}}$

A.P.is also known as arithmetic progression.

Arithmetic Progression is the series of numbers with same difference between them.

The difference between two terms of A.P. is known as the common difference.