What month of the year has 28 days?

I know a nine-letter word having only one vowel.
Do you ?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

If a wheel has 54 spokes, how many spaces are there between the spokes?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

How many times can you subtract the number two from the number fifty?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

It is an eleven letter word.
The first, second, third and fourth letters form a banquet's name.
The fifth, sixth and seventh letters form a car's name.
The eighth, ninth, tenth and eleventh letters form a mode of transport.

Can you identify what word it is?