An archer is shooting arrows from various distances. She shoots at a target from 50 yards, 60 yards, and 70 yards. The probability that she hits within the bullseye from 50 yards is 3/4, the probability that she hits within the bullseye from 60 yards is 2/3, and the probability that she hits within the bullseye from 70 yards is 3/5. What is the probability that she hits the bullseye at least once in three shots, one from each distance listed.
Options:
(A) 9/10
(B) 14/15
(C) 19/20
(D) 29/30
(E) 39/40
Answer and stream of consciousness: (D)
Stream of consciousness: 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 50 yards)*(prob that she misses from 60 yards)*(prob that she misses from 70 yards)
Prob that she misses from 50 yards = 1 - 3/4 = 1/4; Prob that she misses from 60 yards = 1 - 2/3 = 1/3; Prob that she misses from 70 yards = 1 - 3/5 = 2/5
Thus the probability that she misses all shots = (1/4)*(1/3)*(2/5) = 1/30
Thus the probability that she makes at least one shot = 1 - (1/30) = 29/30

A train 160 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40 sec
(B) 50 sec
(C) 44 sec
(D) 24 sec
(E) 60 sec
Answer and stream of consciousness: (D)
Stream of consciousness: Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 160 + 140 = 300 m
Required time = 300 * 2/25 = 24 sec

How many seconds will a train 110 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph?
Options:
(A) 28 sec
(B) 23 sec
(C) 24 sec
(D) 25 sec
(E) 26 sec
Answer and stream of consciousness: (E)
Stream of consciousness: D = 110 + 150 = 260
S = 36 * 5/18 = 10 mps
T = 260/10 = 26 sec

A certain league has two divisions. The respective divisions had 11 and 13 teams qualify for the playoffs. Each division held its own double-elimination tournament -- where a team is eliminated from the tournament upon losing two games -- in order to determine its champion. The four division champions then played in a single-elimination tournament -- where a team is eliminated upon losing one game -- in order to determine the overall league champion. Assuming that there were no ties and no forfeits, what is the maximum number of games that could have been played in order to determine the overall league champion?
Options:
(A) 41
(B) 42
(C) 45
(D) 47
(E) 49
Answer and stream of consciousness:
(D)
Stream of consciousness: Overall, there can be 47 minuses. Tus, it is