What is the Surname of Barbie Doll?

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.

Find the missing number in the image below.

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

What does below Rebus mean ?

esgg sgeg gegs gsge

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

In the given picture, in how many ways can you read the word "Tiger"?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

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?