Coding-Decoding Questions and Answers

Answer: A

Correct answer: ROAAKNM

The letters in even positions are written first, then those in odd positions. MADRAS gives A, R, S from positions two, four and six, followed by M, D, A from positions one, three and five - that is ARSMDA. ARKONAM has seven letters, so the even positions give R, O, A and the odd positions give A, K, N, M, making ROAAKNM.

Answer: D

Correct answer: EOJDJEFM

Reverse the word, then advance every letter by one except the first and the last. COMPUTER reversed is RETUPMOC, and keeping the R and the C while advancing the six between them gives RFUVQNPC. MEDICINE reversed is ENICIDEM; keeping the E and the M and advancing N, I, C, I, D and E gives EOJDJEFM.

Answer: C

Correct answer: PELBORM

The first and last letters stay where they are and everything between them is reversed. FASHION keeps F and N, and ASHIO reversed is OIHSA, giving FOIHSAN. PROBLEM keeps P and M, and ROBLE reversed is ELBOR, so the code is PELBORM.

Answer: C

Correct answer: MNUMNUMNU

Every third letter is taken and the result written three times. BOMBAY has six letters, so the third and sixth - M and Y - give MY, written as MYMYMY. TAMILNADU has nine, so the third, sixth and ninth are M, N and U, and the code is MNUMNUMNU.

Answer: A

Correct answer: BGYEPYK

Both examples use the same rule, a shift of two places back: MIND gives KGLB and ARGUE gives YPESC, the A wrapping round to Y. DIAGRAM therefore gives D→B, I→G, A→Y, G→E, R→P, A→Y, M→K, that is BGYEPYK. The two A’s must both become Y, which settles the answer between the first two options.

Answer: C

Correct answer: HCKVJHWN

Each letter advances two places: TRUTHFUL gives VTWVJHWN. FAITHFUL under the same shift gives F→H, A→C, I→K, T→V, H→J, F→H, U→W, L→N, that is HCKVJHWN. Both words end in the same four letters, so the last four of the code must match those of the example - a useful check.

Answer: B

Correct answer: FKOALD

Every letter moves four places back, as GEORGE to CAKNCA shows. JOSEPH therefore gives J→F, O→K, S→O, E→A, P→L, H→D, that is FKOALD. The wrong options have the right letters in the wrong order, so working through the word in sequence rather than matching letters is what settles it.

Answer: A

Correct answer: IRPICNLAP

The word is divided into groups of three and each group is reversed in place. DIRECTION gives DIR, ECT and ION, which reverse to RID, TCE and NOI, making RIDTCENOI. PRINCIPAL gives PRI, NCI and PAL, which reverse to IRP, ICN and LAP, so the code is IRPICNLAP.

Answer: D

Correct answer: CRIUCALR

The first and last letters stay put and the six between them are exchanged in pairs. CALANDER keeps C and R, and the pairs AL, AN and DE become LA, NA and ED, giving CLANAEDR. CIRCULAR keeps C and R, and the pairs IR, CU and LA become RI, UC and AL, so the code is CRIUCALR.

Answer: B

Correct answer: TOOT

Consonants advance one place and vowels stay as they are. GOLD gives H, O, M, E; COME gives D, O, N, E, the final E being a vowel and so unchanged; and CORD gives D, O, S, E. SONS therefore gives S→T, O unchanged, N→O, S→T, that is TOOT. Treating every letter alike would give TPOT, which is the first distractor.