Question

Find the number of terms of the following arithematic progression
7, 13, 19, 205

Answer 1

Ap: 7, 13, 19....205

Here, a= 7

d = (13-7) = 6

an = 205

Apply last term formula:

an = a + (n - 1) d

=> 205 = 7 + (n - 1) 6

=> 205 = 7 + 6n - 6

=> 6n = 204

=> n = $\rm\frac{204}{6}$

=> n = 34

Therefore, there are 34 terms in the Ap