Aptitude - Time and Distance
Overview Exercise "In the middle of difficulty lies opportunity."
- Albert Einstein
6.
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:
Answer: E
Explanation:
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
x 2 + x - 3 = 0
x + 3)(x - 1) = 0
x = 1 hr. [neglecting the -ve value of x ]
7.
A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.
Answer: A
Explanation:
(1/2)x
+
(1/2)x
= 10
21
24
x +
x = 20
21
24
x = 168 x 20
x =168 x 20
= 224 km.
15
8.
The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:
A. 70 km/hr B. 75 km/hr C. 84 km/hr D. 87.5 km/hr
Answer: B
Explanation:
Let the speed of two trains be 7x and 8x km/hr.
Then, 8x =
400
= 100
4
9.
A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is:
A. 35.55 km/hr B. 36 km/hr C. 71.11 km/hr D. 71 km/hr
Answer: B
Explanation:
Total time taken =
160
+
160
=
9
hrs.
64
80
2
320 x
2
= 71.11 km/hr.
9
10.
A car travelling with
Answer: E
Explanation:
Time taken = 1 hr 40 min 48 sec = 1 hr 40
4
min = 1
51
hrs =
126
hrs.
5
75
75
Let the actual speed be x km/hr.
Then,
5
x x126
= 42
7
75
x =42 x 7 x 75
= 35 km/hr.
5 x 126
Speed of first train = (7 x 12.5) km/hr = 87.5 km/hr.
of its actual speed covers 42 km in 1 hr 40 min 48 sec. Find the actual speed of the car.