Rocket Equation for Booster

[vincentryan]

Hi
Can any one help to write rocket equation with strap on booster.
The exhaust velocity of the booster rocket and the core rocket is same? and
The exhaust velocity of the booster rocket and the core rocket is different?

[aerospaceut10]

If you're just calculating the thrust, for the most part, it can be approximated to adding the thrust generated from the main rocket and the booster rocket together. And...the exhaust velocity depends on the rocket itself, such as the propellant, nozzle design, burning area, etc.