Math, asked by ritiktidke9, 6 months ago

In an A.P a=2, An=40 and Sn=420 then n is

Answers

Answered by Akleshmourya8810

2

Answer:

20

Step-by-step explanation:

An = l

Using formula Sn = n(a+l) /2

420 = n(2+40)/2

420/21 = n

N = 20

Answered by neerajaponnu8

2

Step-by-step explanation:

a is the first term

an is the last term

so by using sn=n/2(a+l)

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