A first order reaction has a rate constant 0.00813 min$$^{-1}$$. How long will it take for 60% completion?

What is the value of rate constant of first order reaction, if it takes 15 minutes for consumption of $$20 \%$$ of reactants?

If concentration of reactant '$$A$$' is increased by 10 times the rate of reaction becomes 100 times. What is the order of reaction, if rate law is, rate $$=k[A]^x$$ ?

A first order reaction has rate constant $$1 \times 10^{-2} \mathrm{~s}^{-1}$$. What time will, it take for $$20 \mathrm{~g}$$ or reactant to reduce to $$5 \mathrm{~g}$$ ?