###
**What is the sum of the first 17 terms of an arithmetic progression if the first term is -20 and last term is 28?**

A. 68
B. 156
C. 142
D. 242
**Answer: Option A**

## Show Answer

Solution(By Apex Team)

First term of AP = a = -20 and last term = l = 28
Number of terms = n = 17
$\begin{aligned}&\text{ Sum of }\mathrm{AP}=\frac{\mathrm{n}}{2}(\mathrm{a}+\mathrm{l})\\
&=\frac{17}{2}(-20+28)\\
&=17\times4\\
&=68\end{aligned}$

## Related Questions On Progressions

### How many terms are there in 20, 25, 30 . . . . . . 140?

A. 22B. 25

C. 23

D. 24

### Find the first term of an AP whose 8th and 12th terms are respectively 39 and 59.

A. 5B. 6

C. 4

D. 3

### Find the 15th term of the sequence 20, 15, 10 . . .

A. -45B. -55

C. -50

D. 0

### The sum of the first 16 terms of an AP whose first term and third term are 5 and 15 respectively is

A. 600B. 765

C. 640

D. 680