How many 90-rm W, 120-rm V light bulbs can be connected to a 20-rm A, 120-rm V circuit without tripping the circuit breaker? (Note: This description of a light bulb gives the power it dissipates when connected to the stated potential difference; that is, a 25-rm W, 120-rm V light bulb dissipates 25 rm W when connected to a 120-rm V line.)