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

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

What word is represented by this rebus?

There is a circular car race track of 10km. There are two cars, Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100 m/seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5 hours all three stop moving.
What is the total distance covered by the bug?

How many sides does a circle have?

Which point will the car reach to go out?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

In the below-given picture of a pretty girl, there is something wrong. Can you find out what it is?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

Can you find out which options fits best with the missing column?

I am a mother. However, I never give birth.

I am a father. However, I never nurse my children.

Wandering is not possible for me, but standing still happens occurs rarely.

Who am I?