Rationale: 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 answer: (E)
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

Rationale: Number of newborns that can die in first month = 1/10 * 400 = 40
Survived = 360
Number of newborns that can die in second month = 1/10 * 360 = 36
Survived = 324
Number of newborns that can die in third month = 1/10 * 324 = 32
Survived = 292
The answer: (D)
Question: In a certain animal population, for each of the first 3 months of life, the probability that an animal will die during that month is 1/10. For a group of 400 newborn members of the population, approximately how many would be expected to survive the first 3 months of life?
Options:
(A) 240
(B) 246
(C) 252
(D) 292
(E) 298

Rationale: Let the time taken be = x
One way distance = 54x
Total distance traveled = 2 * 54x = 108x
Total time taken = x + 2x = 3x
Average speed = 108x/3x = 36
The answer: (C)
Question: A car traveled from San Diego to San Francisco at an average speed of 54 miles per hour. If the journey back took twice as long, what was the average speed of the trip?
Options:
(A) 24.
(B) 32.
(C) 36.
(D) 42.
(E) 44.