Question: An archer is shooting arrows from various distances. She shoots at a target from 60 yards, 70 yards, and 80 yards. The probability that she hits within the bullseye from 60 yards is 2/3, the probability that she hits within the bullseye from 70 yards is 3/5, and the probability that she hits within the bullseye from 80 yards is 1/2. What is the probability that she hits the bullseye at least once in three shots, one from each distance listed.
Options:
(A) 19/20
(B) 29/30
(C) 49/50
(D) 9/10
(E) 14/15 Random thoughts:
The probability that she hits the bullseye at least once = 1 - (the probability that she misses the bullseye every shot)
The probability that she misses every shot = (prob that she misses from 60 yards)*(prob that she misses from 70 yards)*(prob that she misses from 80 yards)
Prob that she misses from 60 yards = 1 - 2/3 = 1/3; Prob that she misses from 70 yards = 1 - 3/5 = 2/5; Prob that she misses from 80 yards = 1 - 1/2 = 1/2
Thus the probability that she misses all shots = (1/3)*(2/5)*(1/2) = 2/30 = 1/15
Thus the probability that she makes at least one shot = 1 - (1/15) = 14/15 The final answer: (E).