Coding and Decoding Questions

The letters at odd positions are each moved two steps backward and those at even positions are each moved two steps forward and the obtained code is reversed to get the corresponding letters of the code.

Following table depicts the code of used letters in the two given words: 

Letters     S     T     A     R     O     E

Code          5     $     *     2     3     @

Therefore, OATS => 3*$5

There is two sequence.
S(odd) P(Even) I(odd) D(even) E(odd) R(even) M(odd) A(even) N(odd)
For odd sequence, we want to write next alphabet of that
and for even, we want to write previous alphabet of that.

TOJCFQNZO is the Answer.

 The alphabets in the given words are coded as follows :

$$\begin{gathered} M I S T A K E N D \\ 9 7 6 5 4 1 2 8 3 \end{gathered}$$

D is coded as 3,

I as 7,
S as 6,
T as 5,
A as 4  and
N as 8.
So, the code for DISTANT is 3765485.

From the given information :

D O W N A M E == 5 @ 9 # 6 % 3
MODE = %@53

Look at the following table which shows the letters and their respective codes :

Letter     A     B     D     E     G     I     M     U     

Code       5     8     3     2     4     1     7     9

Therefore, the code for IMAGE is 17542

Letters at the odd places of the word are written first and these letters are followed by letters at even places.

nec po tam => boys are studying

me tam sam => grapes are sour

tam po me => boys are grapes 

It is clear that "sam" represents "sour" in that code language.