1. A train passes a platform in 36 seconds. The same train passes a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, The length of the platform is
1. None of these
2. 280 meter
3. 240 meter
4. 200 meter
Answer & Explanation Answer:- 3 Explanation :- Speed of the train = 54 km/h = 54 *5/18 m/s = 15 m/s 2. A train moves past a post and a platform 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train? Answer & Explanation Answer:- 1 Explanation :- Let the length of the train be x metres 3. Two trains having equal lengths, take 10 seconds and 15 seconds respectively to cross a post. If the length of each train is 120 meters, in what time (in seconds) will they cross each other when traveling in opposite direction? Answer & Explanation Answer:- 3 Explanation :- Speed of train 1 = (120/10) = 12 m/sec 4. Two trains, one from P to Q and the other from Q to P, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is Answer & Explanation Answer:- 3 Explanation :- Speed = Distance / Time 5. A train having a length of 1/4 mile , is traveling at a speed of 75 mph. It enters a tunnel 3 ½ miles long. How long does it take the train to pass through the tunnel from the moment the front enters to the moment the rear emerges? Answer & Explanation Answer:- 1 Explanation :- Total distance covered = (7/2) + (1/4) miles = 15/4 miles
Length of the train = speed*time = 15 * 20 = 300 m
Let the length of the platform be x metres
Therefore , [ (x + 300) / 36 ] = 15
x + 300 = 540
x = 240 m
1. 79.2 km/hr
2. 69 km/hr
3. 74 km/hr
4. 61 km/hr
& speed of the train be y m/sec
Therefore ,
x/8 = y => x = 8y
& (x + 264)/20 = y
From above equations
(8y + 264)/20 = y
8y + 264 = 20 y
y = 22 m/sec = (22 * 18/5) = 79.2 km/h
1. 10
2. 25
3. 12
4. 20
Speed of train 2 = (120/15) = 8 m/sec
As they are moving in opposite direction
Therefore ,
Relative speed = 12 + 8 = 20 m/sec
Distance covered = 120 + 120 = 240 m
Time = distance/speed = 240/20 = 12 sec
1. 2 : 3
2. 2 :1
3. 4 : 3
4. 3 : 2
Speed of First train = Distance/9
Speed of Second Train = Distance/16
Ratio of their Speeds = (Distance/9) : (Distance/16)
Ratio of their Speeds = (1/9) : (1/16) = (1/3) : (1/4) = 4 : 3
1. 3 min
2. 4.2 min
3. 3.4 min
4. 5.5 min
Time = Distance /Speed
Time taken = (15/4)/75 hrs = (1/20) hrs = (1/20) * 60 = 3 min