In a flight of 6000 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 400 km/hr and time increased by 30 minutes. Find the original duration of flight.

A motor boat whose speed is 15 km/hour in still water goes 30 km downstream and comes back in a total time of 4 hours 30 minutes. Find the speed of the stream.

A car travels 30 km at a uniform speed of 40 km/h and the next 30 km at a uniform speed of 20 km/h . Find its average speed.

After covering a distance of 30 km with a uniform speed there is some defect in a train engine and, therefore, its speed is reduced to 4/5 of its original speed. Consequently, the train reaches its destination late by 45 minutes. Had it happened after covering 18 kilometres more, the train would have reached 9 minutes earlier. Find the speed of the train and the distance of journey.

An express train takes 1 hour less than a passenger train to travel 132 km between Mysore and Bangalore (without taking into consideration the time they stop at intermediate stations). If the average speed of the express train is 11 km/hr more than that of the passenger train, find the average speed of the two trains.

A plane left 30 minutes later than the schedule time. In order to reach its destination 1500 km away in time, it has to increase the speed by 250 km/hour. Find its usual speed.

A train is moving at speed of 78 km/hr. (i) How far will it travel in 20 minutes (ii) Find the time required to cover a distance of 240 km.

A cyclist after travelling a certain distance stopped for 30 minutes to repair the cycle. Then he completed the whole journey of 30 km at half speed and took a total time of 5 hours. If the breakdown has occurred 10 km further off, he would have completed the whole journey in 4 hours. Find where the breakdown occurred and his original speed.

Two trains leave a railway station at the same time. The first train travels due west and the second due north. The first train travels 5 km/hr faster than the second train. If after two hours, they are 50 km apart, find the average speed of each train.

A girl drove to a hospital from her home and noted the odometer reading of her car increased by 12 km. The trip took 18 min. If she returned home by the same path 7h 30 min after she left, what was her average speed and velocity for the entire tip?

An aeroplane flying horizontally 1 km above the ground is observed at an elevation of 60o . After 10 seconds, its elevation is observed to be 30o . Find the speed of the aeroplane in km/hr.