A motor car covers a journey in $9$ h, the first half at $12$ km/h and second half at $15$km/h. Find the distance.

A motorist covers a distance of $39$km in $45$min by moving at a speed of $x$ km/h for the first $15$min, then moving at double the speed for the next $20$min, and then again moving at his original speed for the rest of the journey. Find $x$.

A car travels a distance of $840$ km at a uniform speed. If the speed of the car is $10$ km/h more, it takes two hours less to cover the same distance. The original speed of the car is:

Distance between two towns $P$and $Q$is $240$ km. A motor cycle rider starts from $P$ towards $Q$ at $8$ pm at a speed of $40$ km/h. At the same time, another motor cycle rider starts from $Q$towards $P$at $50$km/h. At what time will they meet?

A car travels $25$ km an hour faster than a bus and takes $10$ hours less in a journey of $500$ km. The speed of the car and bus are given respectively by:

Two trains running in opposite directions cross a man standing on the platform in $54$ sec. and $34$ sec. respectively, and they cross each other in $46$ sec. Find the ratio of their speeds.

What time will be taken by a boat to cover a distance of $64$ km along the stream, if speed of boat in still water is $12$ km/h and speed of stream is $4$km/h?