Question

if in any AP , a= -18.9 , d= 2.5 , an= 3.5 then the value of n is

Answer 1

an=a+(n-1)d

3.5=-18.9(n-1)2.5

3.5+18.9=(n-1)2.5

22.4=(n-1)2.5

22.4/2.5=n-1

8.96=n-1

8.96+1=n

9.96=n

n=10 term

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Answer 2

Answer:

hi, here is your answer.

an = a+(n-1)×d

3.5=-18.9+(n-1)×2.5

3.5+18.9=n-1×2.5

22.4=n-1×2.5

22.4/2.5=n-1

224/25+1=n

so, this is 249/25.

I HOPE IT HELPS.

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