Question 92

The first and last terms of an arithmetic progression are -23 and 42. What is the sum of the series if it has 14 terms?

Solution

In an arithmetic progression with first term, $$a = -23$$ , last term, $$l = 42$$

Number of terms = $$n = 14$$

$$\therefore$$ Sum of A.P. = $$\frac{n}{2} (a + l)$$

= $$\frac{14}{2} (-23 + 42)$$

= $$7 \times 19 = 133$$

=> Ans - (B)

Share on Whatsapp Share on Whatsapp

Create a FREE account and get:

The first and last terms of an arithmetic progression are -23 and ­42. What is the sum of the series if it has 14 terms?