What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

Intelligence Agency need to break the vault but the problem is that they are not able to break the vault.

On the vault, a text is written as:

31 11 33 33 43 45
21 25
31 24 11 31 51 41

To Break the code Intelligence Agency brings a mathematician named Joseph.
Minutes later he deciphers the code.

Whats the code?

A girl says this to her best friend: “I was born in 1955, and I celebrated my 17th birthday last weekend.” Her best friend thinks she’s lying, but she’s actually correct. How is that possible?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Find the missing letter in the last circle logically in the given below picture.

Count the number of triangles in the given picture.

The cream is heavier than Milk. True or False?

There was a greenhouse.
Inside the greenhouse, there is a white house.
Inside the white house, there is a red house.
Inside the red house, there are lots of babies.

What is It?

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

What 5-letter word typed in all capital letters can be read the same upside down?