how to solve this system of kinetic equation

s happening simultaneously

A $+$ B $-->2$A

B $+$ A $-->$ B $+$ D

with rate laws k$1=5$ and k$2-4.$ where A initial is $0$ and B initial is $2$e$6.$ how to find when the population of A is $50\%$ of B$,$ or when D is favored.