  We write explicit contour integral formulas for probability distributions of
the multi-species q-TAZRP and the multi-species ASEP starting with
q-exchangeable initial conditions. The formulas are equal to the corresponding
explicit contour integral formulas for the single-species q-TAZRP
([Korhonen-Lee 2014, Wang-Waugh 2016]) and ASEP [Tracy-Widom 2007], with a
factor in front of the integral.
  For the multi-species q-TAZRP, we use a decomposition theorem for elements of
double cosets of parabolic subgroups in a Coxeter group. The set of
distinguished double coset representatives with minimal length is viewed as a
particle configuration. For the multi-species ASEP we use a more direct proof.
