A boat covers (D+30) km downstream in T hours and the same boat covers D km upstream in (T+5) hours. If the speed of the boat in still water is 15 km/h, then find the speed of the stream (in km/hr).

A car covers a certain distance in 8 hours at a uniform speed. If the speed of the car is increased by 5 km/hr, then the same distance could have been covered in 7 hours 30 minutes. What is the distance covered?

If 20% of 340 is x less than 40% of 480, find x.

A man travels at a speed of 580 kmph and covers a certain distance in 48 minutes. Find the distance covered in metres.

The time taken by a boat to go 18 km downstream is equal to the time taken by it to go 10.8 km upstream. The speed of the boat in still water is 8 km/h. How much time (in hours) will the boat take to go 45 km upstream?