List of top Quantitative Aptitude Questions on Set Theory asked in CAT

Consider two sets A = {2, 3, 5, 7, 11, 13} and B = {1, 8, 27}. Let f be a function from A to B such that for every element b in B, there is at least one element a in A such that f(a) = b. Then, the total number of such functions f is

Let a,b,c be non-zero real numbers such that \(b^2<4ac\), and \(f(x)=ax^2+bx+c\). If the set S consists of all integers m such that \(f(m)<0\), then the set S must necessarily be