Question

Find the sum of the first 10 terms of the A.P. 2,7,12,17……​

Answer 1

Question :-

Find the sum of the first 10 terms of A.P 2,7,12,17....

Answer :-

Given:-

a = 2

d = 5

n = 10

Putting it in the formula

$s_{n} = \frac{n}{2} [2a(n - 1)d ]$

$= \frac{10}{2} [2(2)(10 - 1)5 ]$

$= 5[ 4(9)5]$

$= 5[ 180]$

$= 900$

Therefore the sum of the first 10 term is 900.

Answer 2

Answer:

a=2

d=a2-a1

=7-2

=5

n=10

a10=?

(n =number of the term)

Step-by-step explanation:

now,

use the formula: an= a+( n-1)d

=2+(10-1)×5

=2+9×5

=2+45

=47

hence, the 10th tearm of A.p is 47