If it is possible to make a meaningful word with the 2nd, the 6th, the 9th and the 12th letters of the word 'CONTRIBUTION' , which of the following will be the last letter of that word? If more than one such word can be formed, give 'M' as the answer and if no such word can be formed, give 'X' as the answer.

Binary system is what the representation uses only two digits 0 & 1.

It uses only the powers of 2.

The nine pieces consist of 8 smaller equal pieces and one half cake piece.
Weight of each small piece = 15 g.
So, total weight of the cake = [2 x (15 x 8)]g = 240 g.

Frequency is what means how many times the event occurs in the same period.

Arithmatic mean = sum/members 

=> (1x1 + 2x2 + 3x3 + 4x4 + 5x5 + 6x6 + 7x7) / (1 + 2 + 3 + 4 + 5 + 6 + 7)

=> 140/28 = 5

Let x be number of houses and y be colors.

on the basis of question
x = 4y+1
x = 5(y-1)
on solving these 2 equations x = 25

We know that in A.P series
18th term = a + 17d
29th term = a + 28d
But given
a + 17d = 29..........(i)
a + 28d = 18......... (ii)
Solving equation (i) and (ii), we get
d = -1
put d = -1 in any of the above equations and we get,
a = 46
Now, we know 49th term can be written as, a + 48d
putting the value of a and d in the above equation,
a + 48d = 46 + 48(-1)
= 46 - 48
= -2

Hence, the 49th term is -2.