Question

Which term of an A.P : 4 , 9 , 14 ,...... is 139 ?​

Answer 1

Answer:

28

Step-by-step explanation:

nth term of an AP is given by

$a + (n - 1) \times d$

here, common difference d=5

first term a=4

$4 + (n - 1)5 = 139$

$(n - 1) \times 5 = 135$

$( n - 1) = 27$

$n = 28$

Answer 2

Given:

• A AP is given 4,9,14,.......

To Find:

• Which term of AP is 139.

Answer:

Given AP = 4,9,14.......

Here ,

• Common Difference = (9-4) = 5.
• First term = 4.
• Given term = 139.

We know a formula to find nth term of an AP as,

★ T n = a + ( n - 1 ) d ★

=> T n = 4 + ( n - 1 ) 5 .

=> 139 = 4 + ( n - 1 ) 5.

=> 139 - 4 = ( n - 1 ) 5.

=> ( n - 1 ) 5 = 135.

=> ( n - 1 ) = 135/5.

=> n - 1 = 27.

=> n = 27 + 1.

=> n = 28.

Hence the required answer is 28 .