emrahinci wrote:How many integers n are there such that
r < n < s?
(1) s – r = 5
(2) r and s are not integers.

consider the 1st statement ,

if r =1 then s = 6, then n can be 2,3,4,5 .. that is there are 4 possibilities
if r = -1 then s = 4, then n can be 0,1,2,3 .. 4 possibilities
if r = 1.2 then s = 6.2 , then n can be 2,3,4,5,6 .. that is 5 possibilities
if r = -1.2 then s = 3.8, then n can be -1,0,1,2,3 ,, that is 5 possibilities ..

therefore depending on whether s and r are integers or fractions there are 2 different answers .. since the first statement does not say if s, r are integers or not it is insufficient ..

the 2nd statement says r and s are not integers, this information by itself is useless .. so the 2nd statement is also insufficient ..

combine the 2 statements and we have the answer that n can take 5 possible values ... so the answer is C

Thank you