Determine the rate constant for each of the following first-order reactions. In each case, write the rate law for the rate of loss of A. a) 2 A B + C, given that the concentration of A decreases to one-fourth its initial value in 49 min (b) 2 A B + C, given that [A]0 = 0.038 mol·L-1 and that after 64 s the concentration of B increases to 0.0095 mol·L-1 (c) 2 A 3B + C, given that [A]0 = 0.072 mol·L-1 and that after 8.5 min the concentration of B increases to 0.030 mol·L-1