Let the speed of the stream be ‘x’ km/hr Therefore, speed of the boat in still water = 10x km/hr Upstream speed of the boat = 10x – x = 9x km/hr Downstream speed of the boat = x + 10x = 11x km/hr According to the question, 11x – 9x = 20 => 2x = 20 => x = 10 Therefore, upstream speed of the boat = 9x = 90 km/hr Required time taken = 180/90 = 2 hours
There are two trains A and B. A start from point X at 6 AM towards point Y. Another train B starts at 7 AM from point X. If they meet at 12 PM an...
Train A leaves a station at a certain time and at a fixed speed. After 4 hours, Train B leaves the same station and moves in the same direction at a uni...
Two trains of same length are running in parallel tracks in the same direction with speed 84 km/hr and 120 km/hr respectively. The latter completely cro...
A train takes 5 seconds more to cross a 180-metre-long platform than it takes to cross a pole. If a car running at the speed of 42 m/s takes 80 seconds ...
A train whose speed is 40 m/s crosses a bridge in 20 seconds. Another train which is 80m shorter than the first train crosses the same bridge at the sp...
350 metre long train ‘A’ is running with a speed of 43.2 km/hr. Train ‘B’ which is 387 metre long is running with a speed of 90 km/h in opposite...
A train 300 metre long takes 30 sec to cross a man running at a speed of 6 km/hr in the direction opposite to that of train. What is the speed of the tr...
A train has to cover a distance of 210 km in 14 hours. If it covers half journey in 4/7th time, then the speed of covering the remaining dist...
Train A running at 81 km/h takes 72 sec to overtake train B, when both the trains are running in the same direction, but it takes 36 sec to cross each o...
A train 420 metre long takes 21 sec to cross a man running at a speed of 3 km/hr in the direction same to that of train. What is the speed of the train?
