Answer:
1/7
Explanation:
The following information is missing:
Captain Nadia has a ship, the H.M.S Crimson Lynx. The ship is two furlongs from the dread pirate Tiffany and her merciless band of thieves.
If her ship hasn't already been hit, Captain Nadia has probability 1/2 of hitting the pirate ship. If her ship has been hit, Captain Nadia will always miss.
If her ship hasn't already been hit, dread pirate Tiffany has probability 2/7 of hitting the Captain's ship. If her ship has been hit, dread pirate Tiffany will always miss.
Let's call:
A: captain hits, P(A) = 1/2
A': captain miss, P(A') = 1 - P(A) = 1/2
B: pirate hits
We want to calculate P(A'∩B). This can be computed as follows:
P(A'∩B) = P(A')*P(B|A')
where P(B|A') means pirate hits given that captain miss. We know that P(B|A') = 2/7. Replacing data into the equation:
P(A'∩B) = (1/2)*(2/7) =1/7