Show work please

Substance A decomposes at a rate proportional to the amount of A present. a) Write an equation that gives the amount A left of an initial amount A after time t. b) It is found that 8 lb of A will reduce to 4 lb in 3.7 hr. After how long will there be only 1 lb left? . . . a) Choose the equation that gives A in terms of A, t, and k, where k > 0. O A. A(1) = Apekt O B. A(t) = Ao kt O C. A(1) = Akt O D. A(t) = Ape- kt b) There will be 1 lb left after hr. (Do not round until the final answer. Then round to the nearest whole number as needed.)