Sum of first 55 terms in an A.P. is 3300, find its 28th term.

Given: S₅₅ = 3300 where n = 55

Now, By using sum of n^th term of an A.P. we will find it’s sum

Where, n = no. of terms

a = first term

d = common difference

S_n = sum of n terms

Thus, on substituting the given value in formula we get,

⇒ 3300 = 55 × [ a + 27d]

⇒ a + 27d = 60 ……(1)

We need to find value of 28^th term i.e t₂₈

Now, By using n^th term of an A.P. formula

t_n = a + (n – 1)d

where n = no. of terms

a = first term

d = common difference

t_n = n^th terms

we can find value of t₂₈ by substituting all the value in formula we get,

⇒ t₂₈ = a + (28 – 1) d

⇒ t₂₈ = a + 27 d

From eq. (1) we get,

⇒ t₂₈ = a + 27 d = 60

⇒ t₂₈ = 60