Question

How many multiples of 3 are there among the integers 15 to 105 inclusive?

• A. 30
• B. 31
• C. 32
• D. 33

Answer 1

Answer: (B)

31

Answer 2

The correct option is (B):Multiples of 3 are 15,18,21,…..102,105
This series is AP having first term a=15 , common difference d=3 , last number l=105
Total number of terms be n
using formula $l=a+(n-1)d$
$105=15+(n-1)3$
$(n-1)=30$
$n=31$