Note that "leave orbit" can mean achieving escape velocity (to go to the Moon, Mars, or beyond), or it can mean slowing down and re-entering the atmosphere and eventually landing (or splashing down, or in extreme cases, lithobraking). Or, to be ridiculously pedantic, you can leave one orbit to enter another (i.e., GTO to GEO).
What matters is what your teacher meant by "circle the Earth". As currently phrased, it's not clear. Orbital maneuvers are expressed in terms of change in velocity (ΔV), not the number of times it takes to go around the planet. To go up (to higher orbit or escape velocity), most chemical rockets do it in less than a single orbit. Rockets or spacecraft using electrical propulsion (ion drives) may take several dozen (or several dozens of) orbits to do it.
To hit a specific target, you may have to go into a parking orbit briefly and wait for things to line up (such as on the Apollo missions). But if all you care about is "leaving orbit", regardless of direction, then it only depends on how much oomph you have in your rocket.
To come back down, most rockets and spacecraft thrust just enough to bring their perigee into the uppermost atmosphere, then let drag and friction take over. That usually takes less than a single orbit as well for chemical rockets.
Your teacher is being funny and asking a trick question:
- "In orbit" around what? The Earth? The Sun? The center of the Milky Way?
- Is he/she counting on you "orbiting" the center of the Earth by virtue of standing on its surface, and the Earth spinning on its axis (which isn't really an orbit for a number of reasons, but maybe he/she is using a "horseshoes and hand grenades" definition of orbit)?