Then he did not specify a radio transmitter receiver pair, correct? Visit the Radio Shack and look at their LEDs and detectors. They usually have sample circuits, but all you really need is a small battery, switch and resister for the transmitter, and a 1 transistor amplifier stage at the receiver end. Creeping sophistication will add an oscillator to the transmitter and a tuned circuit to the receiver so it is more sensitive in ambient light. Cary the idea one step further and replace the LED and detector with pieces of wire to act as antennas and you have the original request arrived at empirically instead of by calculation. Personally, I recommend that you do it the other way. Pick a frequency, design an oscillator and feed it into a quarter-wave stub. Feed a receiver with an identical antenna through a tuned LC band pass filter, amplifier and a detector. If you use a LED as the detector, it should glow in the presence of RF.
In either case, your instructor is going to be more interested in seeing the arithmetic than the actual working device.