# Time and Distance - Aptitude Questions and Answers - RejinpaulPlacement

22.
The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hrs, then the speed of the first train is: [I.M.T 2002]

Solution:   Let the speeds of two trains be 7x and 8x km/hr.

Then, 8x = 400/4 = 100
=> x = 100/8 = 12.5

Speed of first train = (7 * 12.5) km/hr = 87.5 km/hr.
23.
A train travels at an average of 50 miles per hour for 2   1/2 hours and then travels at a speed of 70 miles per hour for 1   1/2 hours. How far did the train travel in the entire 4 hours? [IGNOU 2003]

Solution:   Total distance travelled =[(50 * 2   1/2) + (70 * 1   1/2)] miles
= (125 + 105) miles
= 230 miles.
24.
A man in a train notices that he can count 21 telephone posts in one minute. If they are known to be 50 metres apart, then at what speed is the train travelling?

Solution:   Number of gaps between 21 telephone posts = 20

Distance travelled in 1 minute = (50 * 20) m = 1000 m = 1 km.

Speed = 60 km /hr.
25.
Sound is said to travel in air at about 1100 feet per second. A man hears the axe striking the tree, 11/5 seconds after he sees it strike the tree. How far is the man from the wood chopper? [M.B.A 2002]

Solution:   Distance = [1100 * (11/5)] feet = 2420 feet.
26.
An express train travelled at an average speed of 100 km/hr, stopping for 3 minutes after every 75 km. How long did it take to reach its destination600 km from the starting point? [M.A.T 2003]
Answer: c) 6 hrs 21 min

Solution:   Time taken to cover 600 km = (600/100) hrs = 6 hrs.
Number of stoppages = (600/75) - 1 = 7.
Total time of stoppage = (3 * 7) min = 21 min.

Hence, total time taken = 6 hrs 21 min.
27.
A certain distance is covered by a cyclist at a certain speed. If a jogger covers half the distance in double the time, the ratio of the speed of the jogger to that of the cyclist is:

Solution:   Let the distance covered by the cyclist be x and the time taken be y.

Then, Required ratio = (1/2)x/(2y) : x/y = 1/4 : 1 = 1 : 4
28.
A motor car starts with the speed of 70 km/hr with its speed increasing every two hours by 10 kmph. In how many hours will it cover 345 kms? [Bank P.O. 2003]