Question

In an Ap if a=5 , l=21 and s=200 then n is equal to

Answer 1

Step-by-step explanation:

given:-

a=5

l=21

s=200

now,

using the formula,

s=n/2(a+l)

200=n/2(5+21)

200=n/2×26

13n=200

n=200/13...ans...

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Answer 2

Given :-

★ a = 5

★ last term ( l ) = 21

★ sum ( s ) = 200

★ n = ?

Formula :-

→ Sn = n/2 ( a + l ) $\sf$

◆ 200 = n/2 ( 5 + 21 )

◆ 200 × 2 = n ( 25 )

◆ 400 = 25n

◆ n = 400 / 25

◆ n = 16