Need help with Part A & B please! :)

For a first-order reaction, the halt-life is constant. It depends only on the rate constant k and not on the reactant concentration. It is exproased an t1/2=k0.693 For a tocond-orter reaction, the half-ife depends on the rate constant and the concentration of the reactart and so is expressed as t1/2=k]91 Part A A cortain first-order reaction (A products) has a rate constant of 4.80103s1 at 45C. How many minutes does it take tor the concentration of the reactant, [A. to drop to 6.25\% of the original concentration? Express your answer with the appropriate units. Part B A cortain second-order reaction (B pproducts) has a rate constant of 1.70105Mf1. s1 at 27 . C and an initial hathife of 262s. What is the concentration of the reactant B after one half-ife? Express your answer with the appropriate units