A searchlight on top of the watchtower makes 2 revolutions per minute. What is the probability that a man appearing near the tower will stay in the dark for at least 5 seconds?
Choose the most appropriate option.
A) 5/6
B) 5/12
C) 7/12
D) 11/12
E) 11/15
The searchlight completes one revolution every 30 seconds.   The probability that the man's area will be lit up is 5/30=1/6.   The probability that he will stay in the dark is 1-1/6=5/6   The answer is 5/6.
<result>A</result>
A searchlight on top of the watchtower makes 2 revolutions per minute. What is the probability that a man appearing near the tower will stay in the dark for at least 5 seconds?