A brother and sister take their dog for a walk. The sister jogs at an average of 8 mph while the boy walks at an average of 4 mph. The dog runs at a constant 10 mph back and forth between them and he does not stop at any point. After an hour how far will the dog have run?
A train travelling at a speed of 76 mph enters a tunnel 9/2 miles long. The train is 1/4 mile long. How long does it take for the train to pass through the tunnel from the moment the front enters to the moment the rear emerges?
There is a brother and a sister. The boy wants to visit his father in jail, and the sister wants to visit her mother in the hospital. But they both are not allowed in the jail or hospital. They have a gun. What do they do ?
A cyclist covers his outward journey at 15 mph.
The return, over exactly the same distance, is uphill. He completes it at 5 mph.
What is the cyclist's average speed over the entire journey?
Suppose you drive to a picnic spot at 20 mph, then how fast you must go while returning back home on the same route such that your average speed becomes 40 mph ?
A boy started for school which is 12 km away from his home by bicycle at a speed of 8 km/hr but after 15 minutes he remembers that he forgot one of the book at home, so he increases his speed and returns back to home and also reaches his school in time. What is the percentage increase in his speed?
