Rationale: Answer = E. 85 miles
Relational speed = 130 - 100 = 30 miles per hour
In 3 hours, difference = 30 * 3 = 90 miles
Fast train trailing 5 miles, so effective difference = 90 - 5 = 85 miles
The answer: (E)
Question: Two trains are traveling on parallel tracks in the same direction. The faster train travels at 130 miles per hour, while the slower train travels at 100 miles per hour. At 2 o'clock the faster train is 5 miles behind the slower one. How far apart are the two trains at 5 o'clock?
Options:
(A) 60 miles
(B) 80 miles
(C) 90 miles
(D) 120 miles
(E) 85 miles
Reasoning: D = 56 * 5/18 = 25 = 280 90 = 190
Ans: (A)
Question: A train 90 m long running at 56 kmph crosses a platform in 18 sec. What is the length of the platform?
Options:
(A) 190
(B) 200
(C) 180
(D) 881
(E) 271
Rationale: Let the time taken be = x
One way distance = 51x
Total distance traveled = 2 * 51x = 102x
Total time taken = x + 2x = 3x
Average speed = 102x/3x = 34
The answer: (B)
Question: A car traveled from San Diego to San Francisco at an average speed of 51 miles per hour. If the journey back took twice as long, what was the average speed of the trip?
Options:
(A) 24.
(B) 34.
(C) 36.
(D) 42.
(E) 44.
Reasoning: The integer should be divisible by: 4, 5, 6, 7, 8, 9, 10, 11 and 12, that is 2^2, 5, 2*3, 7, 2^3, 3^2, 2*5, 11, 3*2^2. The least common multiple of these integers is the product of 11, 7, 5, 3^2 and 2^3. Then, M/11 is (11 * 7 * 5 * 3^2 * 2^3)/11 = 7*5*9*8 = 2520.
Ans: (E)
Question: If M is the least positive integer that is divisible by every integer from 4 to 12 inclusive, then M/11 is =
Options:
(A) 40320
(B) 27720
(C) 20160
(D) 6720
(E) 2520
Rationale: Total Vehicles = 56
Buses = 18
Private Cars = 38
Total red vehicles = 32
Total red buses = 17
Total Red cars = 15
Total cars that are not red = 38 - 15 = 23
The answer: (E)
Question: In the "Big-Reds" parking lot there are 56 vehicles, 18 of them are buses and the rest are private cars. The color of 32 vehicles is red, from which 17 are buses. How many private cars can be found in the parking lot, which are not colored red?
Options:
(A) 1.
(B) 15
(C) 17
(D) 20
(E) 23
Rationale: Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 350 * 2/35 = 20 sec
The answer: (B)
Question: A train 350 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 18 sec
(B) 20 sec
(C) 76 sec
(D) 15 sec
(E) 17 sec