Question

What is the number of terms in the series 117, 120, 123, 126,.............., 333? 

(a) 72 (b) 73 (c) 76 (d) 79

Answer 1

(b) 117, 120, 123, 126, ........., 333 

Given series is an A.P series with first term, a = 117,

 last term l =333 and common difference, d = 3 

last term, l = a + (n – 1)d 

where, n = number of terms. 

117 + (n – 1)3 = 333 

(n – 1)3 = 216 

n = 73