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101. In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/hr and the time of flight increased by 30 minutes. The duration of the flight is:

[A]. 1 hour

[B]. 2 hours

[C]. 3 hours

[D]. 4 hours

✅ The correct answer is option A.
Let the duration of the flight be x hours.

Then,
600
–
600
= 200

x
x + (1/2)

600
–
1200
= 200

x
2x + 1

x(2x + 1) = 3
2×2 + x – 3 = 0
(2x + 3)(x – 1) = 0
x = 1 hr. [neglecting the -ve value of x]

102. In covering a distance of 30 km, Abhay takes 2 hours more than Sameer. If Abhay doubles his speed, then he would take 1 hour less than Sameer. Abhay’s speed is:

[A]. 5 kmph

[B]. 6 kmph

[C]. 6.25 kmph

[D]. 7.5 kmph

✅ The correct answer is option A.
Let Abhay’s speed be x km/hr.

Then,
30
–
30
= 3

x
2x

6x = 30
x = 5 km/hr.

86. Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction?

[A]. 10

[B]. 12

[C]. 15

[D]. 20

✅ The correct answer is option B.
Speed of the first train =

120

m/sec = 12 m/sec.

Speed of the second train =

120

m/sec = 8 m/sec.

Relative speed = (12 + 8) = 20 m/sec.

Required time =

(120 + 120)

sec = 12 sec.

88. A train 240 m long passes a pole in 24 seconds. How long will it take to pass a platform 650 m long?

[A]. 65 sec

[B]. 89 sec

[C]. 100 sec

[D]. 150 sec

✅ The correct answer is option B.
Speed =

240
m/sec = 10 m/sec.

Required time =

240 + 650
sec = 89 sec.

90. Two trains are running in opposite directions with the same speed. If the length of each train is 120 metres and they cross each other in 12 seconds, then the speed of each train (in km/hr) is:

[A]. 10

[B]. 18

[C]. 36

[D]. 72

✅ The correct answer is option C.
Let the speed of each train be x m/sec.
Then, relative speed of the two trains = 2x m/sec.

So, 2x =
(120 + 120)

2x = 20
x = 10.

Speed of each train = 10 m/sec =

10 x
18

km/hr = 36 km/hr.

61. A train running at the speed of 60 km/hr crosses a pole in 9 seconds. What is the length of the train?

[A]. 120 metres

[B]. 180 metres

[C]. 324 metres

[D]. 150 metres

✅ The correct answer is option D.
Speed =

60 x
5
m/sec
=

50
m/sec.

18
3

Length of the train = (Speed x Time).

Length of the train =

50
x 9
m = 150 m.

Video Explanation: https://youtu.be/q6Xy5JXNp-k

63. A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is:

[A]. 45 m

[B]. 50 m

[C]. 54 m

[D]. 72 m

✅ The correct answer is option B.
2 kmph =

2 x
5

m/sec =
5
m/sec.

18
9

4 kmph =

4 x
5

m/sec =
10
m/sec.

18
9

Let the length of the train be x metres and its speed by y m/sec.

Then,

= 9 and

= 10.

y –
5

y –
10

9y – 5 = x and 10(9y – 10) = 9x
9y – x = 5 and 90y – 9x = 100.
On solving, we get: x = 50.
Length of the train is 50 m.

65. Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

[A]. 12 sec

[B]. 24 sec

[C]. 48 sec

[D]. 60 sec

✅ The correct answer is option B.
Relative speed =
= (45 + 30) km/hr

75 x
5

m/sec

125

m/sec.

We have to find the time taken by the slower train to pass the DRIVER of the faster train and not the complete train.

So, distance covered = Length of the slower train.

Therefore, Distance covered = 500 m.

Required time =

500 x
6

= 24 sec.

125

67. A train moves past a telegraph post and a bridge 264 m long in 8 seconds and 20 seconds respectively. What is the speed of the train?

[A]. 69.5 km/hr

[B]. 70 km/hr

[C]. 79 km/hr

[D]. 79.2 km/hr

✅ The correct answer is option D.
Let the length of the train be x metres and its speed by y m/sec.

Then,
x
= 8 x = 8y

Now,
x + 264
= y

8y + 264 = 20y
y = 22.

Speed = 22 m/sec =

22 x
18

km/hr = 79.2 km/hr.

69. Two stations A and B are 110 km apart on a straight line. One train starts from A at 7 a.m. and travels towards B at 20 kmph. Another train starts from B at 8 a.m. and travels towards A at a speed of 25 kmph. At what time will they meet?

[A]. 9 a.m.

[B]. 10 a.m.

[C]. 10.30 a.m.

[D]. 11 a.m.

✅ The correct answer is option B.
Suppose they meet x hours after 7 a.m.
Distance covered by A in x hours = 20x km.
Distance covered by B in (x – 1) hours = 25(x – 1) km.
20x + 25(x – 1) = 110
45x = 135
x = 3.
So, they meet at 10 a.m.

Author name: Admin