Question

Term of an A. P 3,8,13,18,.......is 78

Answer 1

First term, a = 3  Last term, an = 78  Common difference, d = 5

n = ?

an = a + (n-1)d

=> 78 = 3 + (n-1)5

=> 78 – 3 = (n-1)5

=> 75 = (n-1)5

=> 75/5 = (n - 1)

=>  15 = n – 1

=> n = 15 + 1

=> n = 16