The mean and the variance of five observations are 4 and 5.20, respectively. If three of the observations are 3, 4 and 4 ; then the absolute value of the difference of the other two observations, is :

Let f be a differentiable function such that f(1) = 2 and f '(x) = f(x) for all x $$ \in $$ R R. If h(x) = f(f(x)), then h'(1) is equal to :

Let Z be the set of integers.
If A = {x $$ \in $$ Z : 2^{(x + 2) (x2 $$-$$ 5x + 6)} = 1} and
B = {x $$ \in $$ Z : $$-$$ 3 < 2x $$-$$ 1 < 9},
then the number of subsets of the set A $$ \times $$ B, is

The total number of irrational terms in the binomial expansion of (7^1/5 – 3^1/10)⁶⁰ is :