Question

which term of AP 3, 7, 11, 15.will be 120 more than its 21st term​

Answer 1

Answer:

51th term

Step-by-step explanation:

First term = 3

Common difference = 7 - 3 = 4

Using, aₙ = a + (n - 1)d

  Let nth term be 120 more than its 21st term​:

⇒ 3 + (n - 1)4 = 120 + (3 + (21-1)4)

⇒ (n - 1)4 = 120 + 20(4)

⇒ (n - 1)4 = 120 + 80

⇒ n - 1 = 50

⇒ n = 51

 required term is 51th term of this AP