Question

in an ap 1+2+3.............nterms and An =28 then n=?​

Answer 1

Answer:

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Step-by-step explanation:

a = 1

d = 2 - 1 = 1

tn = 28

a + (n-1)d = 28

1 + n - 1 = 28

n = 28

Answer 2

Step-by-step explanation:

An = a+(n-1)d

28=1+(n-1)1

28-1=(n-1)

27=n-1

27+1=n

28=n