Why is the Hole below a Lock?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

In a football game, Christina defeated Teresa by 2 - 0 but no man from either side scored. How can this be possible?

I am quite hot but become too cold if you remove the first two letters. What am I?

There is a brick of gold and a brick of iron in a boat (both 10-inch blocks), if they are both dropped into the water which will make the water level higher?

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

How many triangles are there on the puzzle below?

What has many teeth, but cannot bite?