A searchlight on top of the watch-tower makes 6 revolutions per minute. What is the probability that a man appearing near the tower will stay in the dark for at least 10 seconds? Choose the correct choice from the following options:
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 1
6 revolutions per minute = 1 revolution every 10 seconds   So no matter what anybody appearing at the tower cannot stay in the dark for more than 10 seconds. This will be our total number of possibilities i.e the denominator.   P(man in dark for at least 10 seconds) = 1 - P (man in dark for max of 10 seconds) = 1 - 10/10 = 1 - 1= 
<gadget id="calculator">1 - 1</gadget>
<output>0</output>
0   or the other way would be:   P(man in dark for at least 10 seconds) is like saying he can be in dark for 5,6,7...all the way to 10 seconds because that is the max. In this approach it would be 10/10= 
<gadget id="calculator">10/10</gadget>
<output>1</output>
1.   Answer is 1
<result>E</result>
A searchlight on top of the watch-tower makes 6 revolutions per minute. What is the probability that a man appearing near the tower will stay in the dark for at least 10 seconds?