Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

If a shopkeeper can only place the weights on one side of the common balance. For example, if he has weights 1 and 3 then he can measure 1, 3 and 4 only. Now the question is how many minimum weights and names of the weights you will need to measure all weights from 1 to 1000? This is a fairly simple problem and very easy to prove also.

Find the next number in the series below

21 32 54 87 131 ?

Find the missing number in the sequence below:

What do you get if you add 2 to 100 four times?

What is the centre of gravity?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

At my favorite fruit stand,
an orange costs 18,
a pineapple costs 27,
and a grape costs 15.
Using the same logic, can you tell how much a mango costs?

who is silent in the parliament?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?