Question
The current age of Derek is twice that of Eve. 7 years
from now, Derek's age will be 1.5 times the age of Fred at that time. If Eve is 5 years younger than Fred, determine the current age of Derek.Solution
Let the present age of Eve be βeβ years. Thus, the present age of Derek = β2eβ years. Let the present age of Fred be βe + 5β years. ATQ, (2e + 7) = 1.5 Γ (e + 5 + 7), Or, 2e + 7 = 1.5e + 18, Or, 2e β 1.5e = 18 - 7, Or, e = 11, Therefore, 2e = 22. Therefore, the current age of Derek = 22 years.
Train 'C' running with a speed of 90 km/hr crosses a pole in 8 seconds. In how much time will train 'C' cross train 'D' whose length is 80 meters more a...
- Train 'A' having a speed of 20 m/s can cross a man in 5 seconds. The length of train 'B' is 100 metres more than the length of 'A'. If the speed of 'B' is ...
A train that is 360 metres long passes a signal post in 18 seconds. How long will it take to pass a bridge that is 240 metres long?
Two poles are positioned at a certain distance from each other. A train traveling at a speed of 90 km/hr passes the first pole in 5 seconds and reaches ...
A train moving at a speed of 72 km/h takes 12.5 seconds to pass a pole. If the train takes 24 seconds to completely cross a platform, what is the lengt...
A train crosses a bridgeΒ in 15 secs while it crosses a man standing on a platform in 8 secs. If the speed of train 108 km/hrs, then what will be the ti...
- A train, running at the speed of 72 km/h, is 300 metres long. How much time (in seconds) will it take to pass over a bridge that is 600 metres long?
- A train can cross a bridge and a pole in 7.2 seconds and 4 seconds respectively. The length of the bridge is 80 metres. Find the time taken by train to cro...
Two trains A and B, were proceeding in the same direction on parallel tracks at 24 km/hr and 78 km/hr respectively. A man noticed that it took exactly 2...
Train βXβ is travelling with a speed of 90 km/hr and crosses a vertical pole in 6 seconds. Train βYβ is 30 metres longer than βXβ and trave...