Decode below three cipher riddles:

26 L of the A
7 D of the W
1000 Y in a M

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

What word does this rebus represent?

meta meta
meta meta

Can you solve the below rebus?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

How many triangles are there on the puzzle below?

There is a five-letter word which has 3 consonants(all are same) and 2 different vowels.
Also, something wrong is associated with the word.

Can you name it?

Why is a river so rich ?

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?