Question

In an AP if a=1, an =20 and Sn= 462

Answer 1

Answer:

In an AP, if a=1,an=20 and Sn= 399, then n=? - 213812.

Answer 2

The value of n=44 and d=19/43

Step-by-step explanation:

The formulae that we have for AP are an=a1+ (n-1)d

and Sn= n/2(2a+(n-1)d),

We have a=1,an=20 and Sn=462

we have n/2(a+ a +(n-1)d)=462

⇒n/2(1+20)=462

⇒n=44

and 1+(44-1)×d=20

⇒d=19/43