For n to be divisible by 15, n needs to be divisible by at least one 3 and one 5.sanjib wrote:If n is an integer, is n/15 an integer?
(1) 3n/15 is an integer.
(2) 8n/15 is an integer
Need explanation please.
1) tells us that n/5 is an integer. we don't know if n is divisible by 3. n can be 15 or n can be 20. Insufficient.
2) 8n/15 = integer. 8 is not divisible by 15, which means n must be divisible by 15 for (8n)/15 to be an integer. Since we know n/15 = integer in this statement, it is sufficient for answering the original question.
(B)
