Question

How many terms in the Arithmetic sequence 3, 7, 11, .....83​

Answer 1

Answer:

21.

Step-by-step explanation:

Given, 3, 7, 11, ......................... 83, is an arithmetic series

where a (1st term) = 3

Common difference is 4

Tₙ (nth term) = 83

Formula for Tₙ = a + (n-1)d

So,

83 = 3 + (n-1) 4

4 (n-1) = 80

n-1 = 20

n = 21

Therefore, 3, 7, 11, ...................... 83 totally consists of 21 terms

Answer 2

Answer:

a = 1

d = 7-3 = 4

tₙ(l) = 83

and, tₙ = a+(n-1)d

      83 = 1+(n-1)4

      83 = 1+4n-4

      83 = 4n -3

      83 + 3 = 4n

      86/4 = n

==>     n = 21

Step-by-step explanation:

Hope it helps :)