Question

Q.2 

Answer 1

Let the given equation has n terms. 

Since, the given equation is an A.P., with a=25 and `d=22-25=-3`

Now, sum of n terms=`115`

`⇒ n/2[2a+(n-1)d]=115`

`⇒n/2[2xx25(n-1)xx(-3)=115]`

`⇒n[50-3n+3]=230`

`⇒53n-3n^2=230`

`⇒3n^2-53n+230=0`

`⇒3n^2-30n-23n+230=0`

`⇒3n(n-10)-23(n-10)=0`

`⇒(n-10)(3n-23)=0`

`⇒n=10 or n=23/3` which is not possible 

⇒n=10 

`∴ x=n^(th)"term "=10^(th) "term"' = a+9d=25+9xx(-3)=25-27=-2`