Jan 2018 APTITUDE FOR GATE -ABHISHEK DASS Course no. 51
Jan 2018 CODING DECODING -ABHISHEK DASS Course no. 51
What is the approach of solving the questions of this section? Observe alphabets or numbers given in the code keenly. Find the sequence it follows whether it is ascending or descending. Detect the rule in which the alphabets/numbers/words follow.
Types of Problems: Type 1: Letter Coding. Type 2: Number Coding. Type 3: Substitution. Type 4: Mixed Letter Coding
Type 1: Letter Coding: Case1: To form the code for another word If in a certain language MYSTIFY is coded as NZTUJGZ, how is NEMESIS coded in that language? Sol. Clearly, each letter in the word MYSTIFY is moved one step forward to obtain the corresponding letter of the code. MYSTIFY NZTUJG Z So, in NEMESIS, N will be coded as O, E as F, M as N and so on. Thus, the code becomes OFNFTJT
Case 2: To find the word by analyzing the given code (DECODING) If in a certain language CARROM is coded as BZQQNL, which word will be coded as HOUSE? SOL: each letter of the word is one step ahead of the corresponding letter of the code BZQQNL HOUSE CARROM IP VT F So, H is coded as I, O as P, U as V, S as T and E as F. HOUSE is coded as IPVTF
Type 2: NUMBER CODING Case 1: when a numerical code values are assigned to words If in a certain language A is coded as 1,B is coded as 2,and so on , how is BIDDIC is coded in that code? SOL: As given the letters are coded as ABCDEFG HI 12345 6 7 89 So in BIDDIC, B is coded as 2, I as 9,D as 4 and C as 3. Thus, BIDDIC is coded as 294493
Type 2: NUMBER CODING Case 2: Number to letter coding. In a certain code, 2 is coded as P, 3 as N, 9 as Q, 5 as R, 4 as A and 6 as B. How is 599423 coded in that code? SOL: Clearly as given 5 is coded as R, 9 as Q, 4 as A, 2 as P, 3 as N. So, 599423 is coded as RQQAPN
SUBSTITUTION In this section an object names are substituted with different object names. We should carefully trace the substitution and answer given question. For Example: If white is called blue, blue is called red, red is called yellow, yellow is called green, green is called black, black is called violet and violet is called orange, what would be the color of human blood? Sol: The color of the human blood is 'red', and as it is given that 'red' is called yellow'. So, the color of human blood is yellow'
In this type of questions, some particular objects are assigned code names. Then a question is asked that is to be answered in the code language. Ex: 1 If cook is called Butter, butter is called manager, Manager is called teacher, teacher is called clerk and clerk is called principle, who will teach in a class? (a) Cook (b) Butter (c) Manager (d) Teacher (e) Clerk Sol: Clearly, teacher, teacher in class and as given teacher is called clerk' So, a clerk will teach in the class. Hence, the answer is (E).
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