<PRE><B>Question 342849</B>
You must go through three tunnels to complete the journey. The probability of their being blocked is 15% for the first, 20% for the second and 15% for the third. What is the probability of completing the journey? 
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P(1st is open) = 0.85
P(2nd is open) = 0.80
P(3rd is open) = 0.85
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To complete the journey, all must be open.
P(all open) = 0.85*0.80*0.85 = 0.5780
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Cheers,
Stan H.</PRE>