If is given that B= Rate of burn of fuel mass

Question

So can we right B=dm/dt or -dm/dt, which of these is accurate?

Answer 1

if m is the mass of the rocket, the -dm/dt is more useful.

Answer 2

Here, m is the mass of the fuel remaining

Answer 3

Mass of system=massofrocket + massoffuel
dMassofSystem/dt=dm/dt and it is negataive. I assume the mass of the rocket does not change.