Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

If eleven plus two equals one, what does nine plus five equal?

How many triangles can you count in the figure given?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

You are a thief and you are being punished for your crime. People have tied your head down on a tree with a rope that has been anchored in the ground. A candle is burning below the rope which is slowly burning it away. Just below your head, a Lion has been left loose and is waiting for you to drop down on the ground so he can have you as his lunch.

You have to survive the scenario. How will you do it?

What four weights can be used to balance from 1 to 30 pounds?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

John was born on March 5, 1970, in Delhi, India. Jacob was born 25 days before John. The year when they took birth, Republic Day fell on Monday.

Can you find out on what day was Jacob born?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?