Question

which term of the ap 5,9,13,17,........is 81

Answer 1

First term ( a) = 5

Common difference (d) = 9 - 5 = 4

Last term (L) = 81

=> a + (n-1) (d) = 81

=> 5 + (n-1)(4) = 81

=> (n-1) 4 = 76

=> n - 1 = 19

=> n = 20

Hence,

20th term of the given AP is 81

Answer 2

Hope it helps you ....