Question

For the A.P.:23,20,17…..which term is -16. ​

Answer 1

Solution:-

Ap => 23 , 20 , 17

=> First term ( a ) = 23

=> Common difference ( d ) = 20 - 23 = -3

To Find

=> Term when T = - 16

Formula

Tₙ = a + ( n - 1 )d

Where

=> Tₙ = - 16

=> a = 23

=> d = - 3

Put the value on formula

=> -16 = 23 + ( n - 1 ) × - 3

=> -16 = 23 - 3n + 3

=> -16 = 26 - 3n

=> - 16 - 26 = - 3n

=> - 42 = - 3n

=> n = 42/3

=> n = 14

Answer is 14

Answer 2

Answer:

Here

First term, a = 23

Common difference, d = 20 - 23 = - 3

nth term = - 16

a + (n - 1)d = - 16

23 -3(n - 1) = - 16

23 - 3n + 3 = - 16

26 + 16 = 3n

3n = 42

n = 14