Find (61 + 62 + 63 + ……… +110) = ?
Expression : (61 + 62 + 63 + ……… +110)
This is an arithmetic progression with first term, $$a = 61$$ , last term, $$l = 110$$ and common difference, $$d = 1$$
Let number of terms = $$n$$
Last term in an A.P. = $$a + (n - 1)d = 110$$
=> $$61 + (n - 1)(1) = 110$$
=> $$n - 1 = 110 - 61 = 49$$
=> $$n = 49 + 1 = 50$$
$$\therefore$$ Sum of A.P. = $$\frac{n}{2} (a + l)$$
= $$\frac{50}{2} (61 + 110)$$
= $$25 \times 171 = 4275$$
=> Ans - (A)
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