Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration,the order of reaction is

The half-life of a reaction is found to be inversely proportional to the cube of its initial concentration. The order of the reaction is:

For the reaction $A + B \to \text{products}$,it is found that the rate of the reaction is proportional to the concentration of $A$,but it is independent of the concentration of $B$. Then:

Which of these does not influence the rate of reaction?

Fill in the blanks:
$1.$ The rate of a zero order reaction depends on the ........... concentration of the reactant.
$2.$ The molecularity of the slow step is equal to the ........... of the overall reaction.
$3.$ Rate $=$ ........ $[A]^x [B]^y$

For the reaction $2A + B \rightarrow \text{Product}$,the rate constant $(K)$ is $2.5 \times 10^{-5} \text{ L mol}^{-1} \text{ s}^{-1}$ after $15 \text{ s}$,$2.60 \times 10^{-5} \text{ L mol}^{-1} \text{ s}^{-1}$ after $30 \text{ s}$,and $2.55 \times 10^{-5} \text{ L mol}^{-1} \text{ s}^{-1}$ after $50 \text{ s}$. What is the order of the reaction?