Robot motors for EDC (Engineering Design Competition)?

I am building a robot for an engineering competition and this is my first time and I have little experience with electrical engineering. We are required to use a 7.2 Volt NiCd battery pack and I want to connect 3 motors to it. I want a two (2) 72 RPM @ 12 VDC 25 mA, 144 RPM @ 24Vdc 30mA gearhead motors for wheels as well as a single (1) 3 RPM, 6 Vdc, 75 mA. 6 RPM, 12 Vdc, 85 mA gearhead motor for an arm. Will this battery pack support those motors and could you explain what the two different RPM settings on the motors mean? If these do not work could someone give me an example of ones that do work and why?