q: There are 20 balls in a jar. You take out 2 blue balls without putting them back inside, and now the probability of pulling out a blue ball is 1/5. How many blue balls were there in the beginning?
Options:
(A) 12.
(B) 9.
(C) 8.
(D) 7.
(E) 6.
a: Stream of consciousness: 12 = 3 blue balls + 18 / 2 The answer is (A).

question: Eddy and Freddy start simultaneously from city A and they travel to City B and City C respectively. Eddy takes 3 hours and Freddy takes 3 hours to complete the journey. If the distance between City A and City B is 600 kms and City A and City C is 300 kms. What is the ratio of their average speed of travel? (Eddy: Freddy)
Options:
(A) 2/1
(B) 3/8
(C) 8/5
(D) 5/8
(E) 5/3
answer: Stream of consciousness: Distance traveled by Eddy = 600 km
Time taken by Eddy = 3 hours
Average speed of Eddy = 600/3 = 200 km/hour
Distance traveled by Freddy = 300 km
Time taken by Freddy = 3 hours
Average speed of Freddy = 300/3 = 100 km/hour
Ratio of average speed of Eddy to Freddy = 200/100 = 2/1 The answer is (A).

q: Find the average of the first 19 natural numbers?
Options:
(A) 8
(B) 9
(C) 10
(D) 11
(E) 12
a: Stream of consciousness: Average of the first 'n' natural numbers = (n + 1)/2
We get (19 + 1)/2 = 10 The answer is (C).

question: John makes $50 a week from his job. He earns a raise and now makes $70 a week. What is the % increase?
Options:
(A) 16%
(B) 16.66%
(C) 18%
(D) 21%
(E) 40%
answer: Stream of consciousness: Increase = (20/50)*100 = 40%. The answer is (E).

q: The flow of water through a drainage pipe was monitored for a 3-hour period. In the second hour, the rate of flow was 24 gallons per hour, which was 50 percent faster than the rate of flow for the first hour. If 25 percent more water flowed through the pipe in the third hour than it did in the second, how many gallons of water flowed through the pipe during the entire three hours?
Options:
(A) 61.25
(B) 62.5
(C) 63.75
(D) 70.0
(E) 77.5
a: Stream of consciousness: Rate of flow of water in second hour = 24 gallons per hour
Rate of flow of water in first hour = 24/(3/2) = 16 gallons per hour
Rate of flow of water in third hour = (125/100)* 24 = (5/4) * 24 = 30 gallons per hour
Number of gallons of water that flowed through the pipe during the entire 3 hours = 16+24+30 = 70 gallons The answer is (D).

q: A train 250 m long running at 72 kmph crosses a platform in 20 sec. What is the length of the platform?
Options:
(A) 150m
(B) 200m
(C) 250m
(D) 270m
(E) 300 m
a:
Stream of consciousness: D = 72 * 5/18 = 20 = 400 250 = 150m The answer is (A).