Question

.If first term is 5 , 10th term is 23 , the sum of 10 terms is ​

Answer 1

Answer:

a=5

a10=23

a+9d=23

5+9d=23

9d=18

d=2

$sum = \frac{10}{2} (2 \times 5 + (10 - 1)2) \\ sum = 5(10 + 18) \\ sum = 5 \times 28 \\ sum = 140$

Answer 2

Answer:

answer is 140

Step-by-step explanation:

if,

a= 5.........(1)

a10 a + 9d = 23......(2)

(1) - (2)

a = 5

a + 9d = 23

- - -

-----------------

0 -9d = -18

d = -18/-9

d = 2

now sum of 10 term

S10 = n/2 { 2a + ( n-1 ) d }

= 10/2 { 2*5 + ( 10-1 ) 2 }

= 5 { 10 + 9*2 }

= 5 { 10+18 }

= 5 * 28

= 140