0 votes 0 votes in a set of odd numbers less than 500, What is the total number of numbers divisible by 15? Dulqar asked Feb 3, 2017 Dulqar 1.1k views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Kantikumar commented Feb 3, 2017 reply Follow Share Total numbers divisible by 15 below 500 = $\left \lfloor \frac{500}{15} \right \rfloor$ = 33. Total odd numbers = $\left \lceil \frac{33}{2} \right \rceil$ = 17 1 votes 1 votes Dulqar commented Feb 4, 2017 reply Follow Share @Kantikumar What is the logic behind 33/2 ?? is 2 becaause set of odd numbers differs by 2 ? Had the question been " In a set of numbers which are multiple of 7 " Then would the answer be 33/ 7 ? 0 votes 0 votes Kantikumar commented Feb 4, 2017 reply Follow Share See, numbers divisible by 15 are in order of 15, 30, 45, 60, so on. We are getting 1 odd then 1 even again odd and even, so on. Therefore we'll have to divide by 2 here. For multiple of 7 : $\left \lfloor \frac{500}{7} \right \rfloor$ = 71 Odd numbers = $\left \lceil \frac{71}{2} \right \rceil$ = 36 1 votes 1 votes Dulqar commented Feb 4, 2017 reply Follow Share @Kantikumar Actually I was asking the other way , " In a set of numbers which are multiple of 7 and less than 500 , What is the total number of numbers divisible by 15 " Here we will divide 33 / 7 , right ? 0 votes 0 votes Kantikumar commented Feb 4, 2017 reply Follow Share Nopes. Here required number will be multiple of both 7 and 15. $\therefore$LCM(7,15) = 105 Total numbers divisible by 105 = $\left \lfloor \frac{500}{105} \right \rfloor$ = 4 Total odd numbers = $\frac{4}{2}$ = 2. 1 votes 1 votes Please log in or register to add a comment.