Teresa has a clock that gives off a signal every 60 minutes, another clock that gives off a signal every 150 minutes, and a third one that gives off a signal every 360 minutes. At 9 am, all three clocks coincide and give off the signal at the same time. a) What is the least amount of hours it will take for the clocks to coincide again? b) At what time will they all give off the signal?