Question
A person is jogging at 10 m/sec in the same direction of
a train. The train crosses him in 6 seconds. If the speed of the train is 90 km/hr, find the time it takes to cross a tunnel of 60 metres.Solution
Train speed = 90 × (5/18) = 25 m/sec
Relative speed = 25 - 10 = 15 m/sec
L / 15 = 6 ⇒ L = 90 metres
Time to cross the tunnel = (90 + 60)/25 = 150/25 = 6 seconds
A boat can cover 210 km in downstream in 10 hours and 160 km in upstream in 8 hours. Find the distance travelled by the boat in still water in 6 hours.
The circumference of the two circles is 110 cm and 330 cm respectively. What is the difference between their radii?
Arjun covers a distance of 96 km downstream and then returns the same distance upstream, completing the entire journey in 7 hours. Given that the speed ...
The speed of a boat in still water is 7 km/hr and the speed of the stream is 2.5 km/hr. A man rows to a place at a distance of 42.75 km and comes back t...
Speed of boat is 20 km/hr. Speed of the stream is 20% less than speed of boat. Then find time taken by boat to go 90 km downstream.
The respective ratio between the time taken by a boat to travel the same distance downstream in stream A and that in stream B is 7 : 5. The speed of the...
A boat can cover 185 km in downstream in 5 hours and 120 km in upstream in 12 hours. Find the speed of boat in still water.
A boat travels from point 'Y' to point 'Z' downstream and then returns to point 'X', which is located midway between 'Z' and 'Y'. The entire trip takes ...
The ratio of the speed of the boat in upstream to that of in downstream is 7:10, respectively. If the speed of the current is 12 km/h, then find the spe...
A boat can cover 60 km in still water and 75 km in downstream in 4 hours and 3 hours respectively. Find the time taken by the boat to cover 60 km upstre...
Relevant for Exams:
