1. A train 300 metres long is running at a speed of 90 km/hr. How many seconds will it take to cross a 200 metres long train running in the same direction at a speed of 60 km/hr?
A. 70 sec
B. 50 sec
C. 60 sec
D. None of these
Answer: Option B
Explanation: Here L1 = 300m, L2= 200m
S1 = 90 km/hr and S2= 60 km/hr
S1 = S2 = 90 - 60 = 30 km/hr = 30 x[latex]\frac{5}{18}[/latex] m/s
Time Taken = [latex]\frac{L1 + L2}{S1 - S2}[/latex]
= [latex]\frac{300 + 200}{30 × 5/18}[/latex]
= [latex]\frac{500 × 18 }{30 × 5}[/latex] = 60 sec
2. Two trains are running in opposite directions with the same speed. If the length of each train is 135 metres and they cross each other in 18 seconds, the speed of each train is
A. 29 km/hr
B. 35 km/hr
C. 27 km/hr
D. None of these
Answer: Option C
Explanation: Let the speed of each tarin be x m/sec
We have L1 = L2 = 135 m
And S1 = S2 = xm/sec
Therefore time taken = [latex]\frac{L1+ L2}{S1+ S2}[/latex]
18 = [latex]\frac{135 + 135}{x + x}[/latex] = [latex]\frac{270}{2 × 18}[/latex] x [latex]\frac{18}{5}[/latex]km/hr
3. A and B are two stations. A train goes from A to B A at 64 km/hr and returns to A at a slower speed. If its average speed for the whole journey is 56 km/hr, at what speed did it return?
A. 48 km/hr
B. 49.77 km/hr
C. 30 km/hr
D. 47.46 km/hr
Answer: Option B
Explanation: Let the required speed by x km/hr
Then [latex]\frac{2 × 64 × x}{64 + X}[/latex] = 60
128X = 64 X 56 + 56 X
X = [latex]\frac{64 × 56}{72}[/latex] = 49.77km/hr
4. Excluding stoppages, the speed of a bus is 54 km/hr and including stoppages, it is 45 km/hr. For how many minutes does the bus stop per hour?
Answer: Option B
Explanation: Due to stoppages, it covers 9km less per hour.
Time is taken to cover 9 km = ([latex]\frac{9}{54}[/latex]×60)min
= 10 min
So, the bus stops for 10 min. per hr.
5. Excluding stoppages, the speed of a bus is 54 kmph and including stoppages, it is 45 kmph. For how many minutes does the bus stop per hour?
Answer: Option B
Explanation: Due to stoppages, it covers 9 km less.
Time taken to cover 9 km = [[latex]\frac{9}{54}[/latex] x 60]min = 10 min.