The letter-code for the sth letter is
(2s-1) th letter for s = 1, 2,3,4,5,6,7,(2s) th letter for s = 8,9,10,11,12,13,(s-d)
the letter for s=14,15,16.17,18,19,20
where d=12,11,10,9,8,7,6,(s-d)the letter for s=21,22,
23,24,25.26, where d=6,5,4,3,2,1. In case of decoding the
inverse process is followed.
How many letters are coded consecutive in order
according to english alphabet in the letter-coding ?

Options

A. Zero
B. One
C. Three
D. Two

Answer

d

Explanation

Letter - code for the Sth letter for
`underset(S=" "1,2,3,4,5,6,7)(" ""A B C D E F G")`
`rArr(2s-1)` th letter i.e., (2 `xx` 1-1) = 1st letter = A
Similarly, 3rd letter = C , 5th letter= E, 7 th letter = G,
9th letter = I, 11th letter = K , 13 th letter = M .
Letter - code for the sth letter for
`underset(S=" "8,9,10,11,12,13)("H I J K L M")`
`rArr(2s)` th letter i.e., 2 `xx` 8 = 16 th letter = P.
Similarly, 18th letter = R , 20 th letter = T,
22nd letter = V , 24 th letter = X , 26 th letter = Z.
Letter - code for `underset(S= (14,15,16,17,18,19,20))("N O P Q R S T")`
`rArr(s-d)` th letter ie.,(14-12)=2nd letter =B.
Similarly, 4th letter= D , 6th letter = F , 8th letter = H ,
10 th letter = J , 12 th letter = L, 14th letter = N .
Letter - code for `underset(S=" "21,22,23,24,25,26)("U V W X Y Z")`
`rArr(s-d)` th letter i.e., (21-6) = 15 th letter =O
Similarly, 17th letter = Q : 19 th letter = S,
21st letter = U , 23rd letter = W , 25 th letter= Y .
so ,the table is as follows :

`underset("letter")(.B.)overset(code)rArr underset(code)(.C.)," "underset("letter")(.Z.)overset(code)rArr underset(code)(.Y.)`