What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

What question can you never answer yes to?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

What has 13 hearts but no other organs?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

What goes up but never comes down?

What is 3/7 chicken, 2/3 cat and 2/4 goat?

An old Woman left INR 33,333 to be divided equally among two fathers and two sons and each was to receive INR 11,111.
How was this possible?

Can you find the least possible number such that

If the number is divided by 3, it gives the remainder of 1;
If the number is divided by 4, it gives the remainder of 2;
If the number is divided by 5, it gives the remainder of 3;
If the number is divided by 6, it gives the remainder of 4.