Question

Which term of ap 3 15 27 39 will be 120 more than its 64th term?

Answer 1

please see the attached photo for your answer

Answer 2

Answer:

Required term is 74th term of the AP.

Step-by-step explanation:

Given terms of an AP are 3 , 15 , 27 , 39.

Here,

First term of the AP = a = 3

Common difference between the terms = 27 - 15 = 15 - 3 = 12

From the properties of AP : -

• nth term = a + ( n - 1 )d, where a is the first term, d is the common difference  between terms and n is the number of terms.

Let the term which is 120 more than its 64th term is nth term.

= > nth term = 64th term + 120

= > nth term = a + ( 64 - 1 )d + 120

= > a + ( n - 1 )d = a + 63( 12 ) + 120

= > ( n - 1 )12 = 756+ 120

= > n - 1 = 876 / 12

= > n - 1 = 73

= > n = 73 + 1

= > n = 74

Hence the required term is 74th term of the AP.