In the phenomenon of autocatalysis,......

For the following parallel chain reaction,what will be the value of the overall half-life of $A$ in minutes?
Given that $\frac{[B]_t}{[C]_t} = \frac{16}{9}$
$A \xrightarrow{k_1 = 2 \times 10^{-3} \ s^{-1}} 4B$
$A \xrightarrow{k_2} C$

Which of the following statements is correct?

Under the same reaction conditions, initial concentration of $1.386 \ mol \ dm^{-3}$ of a substance becomes half in $40 \ s$ and $20 \ s$ through first-order and zero-order kinetics respectively. Ratio $\left(\frac{k_{1}}{k_{0}}\right)$ of the rate constants for first-order $\left(k_{1}\right)$ and zero-order $\left(k_{0}\right)$ of the reactions is

$A$ substance $S$ undergoes two reactions under similar reaction conditions:
$\mathop S\limits_{(2.0 \ M)} \xrightarrow{K_0} X$ (zero order)
$\mathop S\limits_{(2.0 \ M)} \xrightarrow{K_2} Y$ (second order)
The time taken for the concentration of $S$ to become half is $40 \ s$ and $10 \ s$ for the zero-order and second-order reactions,respectively. What is the value of the ratio $K_0 / K_2$?

For a chemical reaction, half-life period $(t_{1/2})$ is $10 \ minutes$. How much reactant will be left after $20 \ minutes$ if one starts with $100 \ moles$ of reactant and the order of the reaction is $(i)$ zero, $(ii)$ one, and $(iii)$ two?