Question

What is the sum of first 12 terms of an arithmetic progression, if the first term is -19 and the last term is 36 ?

192
230
102
214
None of these Workspace​

Answer 1

Answer:

102

Step-by-step explanation:

a =-19

l = 36

n =12

sum of n terms =

$\frac{n}{2} (a + l)$

$= \frac{12}{2} ( - 19 + 36)$

$= 6 \times 17$

$= 102$

Answer 2

Step-by-step explanation:

a= -19

$a_{n} = 36$

$s_{12}= \frac{n}{2}(a + a_{n} )$

= $\frac{12}{2} (-19 + 36)$

= 6 x 17

= 102