If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

What does it mean?

Can you solve the photo plexer logic ?

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

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?