In a certain code ‘RAIL’ is written as ‘KCTN and ‘SPEAK’ is written as ‘CGRUM’. How will ‘AVOID’ be written in that code ?

The pattern here followed is that the last letter of the word is excluded.

The word RAIL is divided into two parts : RAI & L

I : RAI - KCT

The diagonally opposite element is substituted by its 2nd to the right alphabet in the English alphabetical series.

=> R is substituted by T at its diagonally opposite position. Similarly, A is substituted by C at its diagonally opposite position and I by K.

II : L - N

The last letter i.e. L is substituted by the alphabet second to its right i.e. N

Similar pattern can be observed for SPEAK

Thus, code for AVOID

AVOI - KQXC

D - F

=> AVOID - KQXCF