The level of radiation in the control room of a nuclear reactor is to be automatically monitored by a Geiger counter. The monitoring device works as follows: Every tenth minute the number (frequency) of "clicks" occurring in t seconds is counted automatically. A scheme is required such that if the frequency exceeds a number c an alarm will sound. The scheme should have the following properties: If the number of clicks per second is less than 4, there should be only 1 chance in 500 that the alann wiJJ sound, but if the number reaches 16, there should be only about I change in 500 that the alarm will not sound. What values should be chosen fort and c?