Some please help me with an ODE problem!!

So for my Kinetics class I'm trying to derive a function in Mathcad to get the result I need to answer a question in the book. First I need to verify that Mathcad can do this. Can someone please tell me how to do this? Thanks!

Irreversible 1st order reaction in PFTR (Parallel Reaction)

A→B r1=k1*Ca

A→C r2=k2*Ca

dCa/dt=-k1*Ca-k2*Ca

dCb/dt=k1*Ca

dCc/dt=k2*Ca

Boundary Condition: Ca=Ca0

Ca(t)=Ca0*exp(-(k1+k2)*t)