Coding-Decoding: Letter Shifts and Substitution — MCQs with Answers (Set 1)

In ART to BQU, the 1st and 3rd letters shift forward by one, and the 2nd letter shifts back by one (A+1=B, R-1=Q, T+1=U). Applying that to TAR: T+1=U, A-1=Z, R+1=S, giving USZ.

Substitute the real operations in every option: + becomes ÷, − becomes ×, × becomes −, and ÷ becomes +. Checking option A: 11 + 9 − 9 × 2 becomes 11 ÷ 9 × 9 − 2. Division and multiplication come first, worked left to right. 11 ÷ 9 times 9 cancels out to 11, then 11 − 2 = 9, not 2. Checking option B: 14 − 5 ÷ 13 × 13 becomes 14 × 5 + 13 − 13. 14 × 5 = 70, then 70 + 13 = 83, then 83 − 13 = 70, not 9. Checking option C: 4 × 4 + 4 ÷ 4 becomes 4 − 4 ÷ 4 + 4. 4 ÷ 4 = 1, then 4 − 1 = 3, then 3 + 4 = 7, not 17. Checking option D: 20 ÷ 12 × 6 − 3 becomes 20 + 12 − 6 × 3. 6 × 3 = 18, then 20 + 12 = 32, then 32 − 18 = 14. This matches the stated total, so option D is correct. Only option D holds true, so option D is correct.

Substitute the real operations: − becomes ×, × becomes +, + becomes ÷, and ÷ becomes −. The expression becomes: (9 × 3) + 8 ÷ 4 − 6. Solve the bracket first. 9 × 3 = 27. The expression is now: 27 + 8 ÷ 4 − 6. Division comes next. 8 ÷ 4 = 2. Working left to right, 27 + 2 = 29, then 29 − 6 = 23. So the value of the expression is 23.

Substitute the real operations: ÷ becomes ×, + becomes −, × becomes +, and − becomes ÷. The expression becomes: 30 × (5 − 1) + 8 ÷ 4. Solve the bracket first. 5 − 1 = 4. The expression is now: 30 × 4 + 8 ÷ 4. Multiplication and division come next. 30 × 4 = 120, and 8 ÷ 4 = 2. Finally, 120 + 2 = 122. So the value of the expression is 122.

Substitute the real operations: + becomes −, − becomes +, × becomes ÷, and ÷ becomes ×. The expression becomes: (26 − 8) ÷ 3 + 5 × 4. Solve the bracket first. 26 − 8 = 18. The expression is now: 18 ÷ 3 + 5 × 4. Division and multiplication come next. 18 ÷ 3 = 6, and 5 × 4 = 20. Finally, 6 + 20 = 26. So the value of the expression is 26.

Substitute the real operations: − becomes ×, + becomes ÷, × becomes −, and ÷ becomes +. The expression becomes: 16 × 8 ÷ 4 − 2 + 4. Multiplication and division come first, worked left to right. 16 × 8 = 128, then 128 ÷ 4 = 32. The expression is now: 32 − 2 + 4. Working left to right, 32 − 2 = 30, then 30 + 4 = 34. So the value of the expression is 34.

Substitute the real operations: ÷ becomes −, − becomes ×, + becomes ÷, and × becomes +. The expression becomes: 24 − 4 × 6 ÷ 3 + 2. Multiplication and division come first, worked left to right. 4 × 6 = 24, then 24 ÷ 3 = 8. The expression is now: 24 − 8 + 2. Working left to right, 24 − 8 = 16, then 16 + 2 = 18. So the value of the expression is 18.

Substitute the real operations: ÷ becomes ×, + becomes ÷, − becomes +, and × becomes −. The expression becomes: 8 × 5 ÷ 4 + 6 − 9. Multiplication and division come first, worked left to right. 8 × 5 = 40, then 40 ÷ 4 = 10. The expression is now: 10 + 6 − 9. Working left to right, 10 + 6 = 16, then 16 − 9 = 7. So the value of the expression is 7.

Substitute the real operations: − becomes ÷, + becomes ×, × becomes −, and ÷ becomes +. The expression becomes: 10 ÷ 4 × 6 − 3 + 2. Division and multiplication come first, worked left to right. 10 ÷ 4 = 2.5, then 2.5 × 6 = 15. The expression is now: 15 − 3 + 2. Working left to right, 15 − 3 = 12, then 12 + 2 = 14. So the value of the expression is 14.

Substitute the real operations: + becomes ×, − becomes +, × becomes ÷, and ÷ becomes −. The expression becomes: 6 × 5 + 12 ÷ 4 − 2. Multiplication and division come first. 6 × 5 = 30, and 12 ÷ 4 = 3. The expression is now: 30 + 3 − 2. Working left to right, 30 + 3 = 33, then 33 − 2 = 31. So the value of the expression is 31.

Substitute the real operations: + becomes −, − becomes ÷, × becomes +, and ÷ becomes ×. The expression becomes: 12 − 5 + 6 ÷ 4 × 2. Division and multiplication come first, worked left to right. 6 ÷ 4 = 1.5, then 1.5 × 2 = 3. The expression is now: 12 − 5 + 3. Working left to right, 12 − 5 = 7, then 7 + 3 = 10. So the value of the expression is 10.

Substitute the real operations: + becomes −, − becomes ×, × becomes ÷, and ÷ becomes +. The expression becomes: 15 − 3 ÷ 6 × 4 + 2. Division and multiplication come first, worked left to right. 3 ÷ 6 = 0.5, then 0.5 × 4 = 2. The expression is now: 15 − 2 + 2. Working left to right, 15 − 2 = 13, then 13 + 2 = 15. So the value of the expression is 15.

Substitute the real operations: + becomes −, − becomes +, × becomes ÷, and ÷ becomes ×. The expression becomes: 20 − 8 ÷ 4 + 6 × 2. Division and multiplication come first. 8 ÷ 4 = 2, and 6 × 2 = 12. The expression is now: 20 − 2 + 12. Working left to right, 20 − 2 = 18, then 18 + 12 = 30. So the value of the expression is 30.

Under this rule, × actually means ÷, and ÷ actually means ×. Rewrite the expression with the real operations: 20 ÷ 5 × 4 ÷ 2. Multiplication and division rank equally, so work left to right. First, 20 ÷ 5 = 4. Next, 4 × 4 = 16. Finally, 16 ÷ 2 = 8. So the value of the expression is 8.

Under this rule, + actually means −, and − actually means +. Rewrite the expression with the real operations: 25 − 10 + 4 − 6 + 3. First, 25 − 10 = 15. Next, 15 + 4 = 19. Next, 19 − 6 = 13. Finally, 13 + 3 = 16. So the value of the expression is 16.

Under this rule, ÷ actually means ×, and × actually means ÷. Rewrite the expression with the real operations: 60 × 5 ÷ 4 × 2. Multiplication and division rank equally, so work left to right. First, 60 × 5 = 300. Next, 300 ÷ 4 = 75. Finally, 75 × 2 = 150. So the value of the expression is 150.

Under this rule, − actually means +, and + actually means −. Rewrite the expression with the real operations: 40 + 12 − 8 + 5. First, 40 + 12 = 52. Next, 52 − 8 = 44. Finally, 44 + 5 = 49. So the value of the expression is 49.

Under this rule, × actually means ÷, and ÷ actually means ×. Rewrite the expression with the real operations: 24 ÷ 4 × 2 ÷ 3. Multiplication and division rank equally, so work left to right. First, 24 ÷ 4 = 6. Next, 6 × 2 = 12. Finally, 12 ÷ 3 = 4. So the value of the expression is 4.

Under this rule, + actually means −, and − actually means +. Rewrite the expression with the real operations: 18 − 7 + 5 − 9. First, 18 − 7 = 11. Next, 11 + 5 = 16. Finally, 16 − 9 = 7. So the value of the expression is 7.

Check the first equation. Multiply 3 x 4, which is 12. Reverse its digits: 12 becomes 21. This matches. Check the second equation. Multiply 6 x 7, which is 42. Reverse its digits: 42 becomes 24. This also matches. The hidden rule is: a △ b means multiply first, then reverse the digits of the product. Apply it to 8 △ 9. Multiply: 8 x 9 = 72. Reverse its digits: 72 becomes 27.

Check the first equation. Double 7: 7 x 2 = 14. Subtract 3, then add 1: 14 – 3 + 1 = 12. This matches. Check the second equation. Double 9: 9 x 2 = 18. Subtract 4, then add 1: 18 – 4 + 1 = 15. This also matches. The hidden rule is: a $ b means (2 x a) – b + 1. Apply it to 11 $ 5. Double 11: 22. Then 22 – 5 + 1 = 18.

Look at the given equation. Add the two numbers: 3 + 5 = 8. Double that sum: 8 x 2 = 16. This matches. The hidden rule is: a * b means (a + b), then doubled. Apply the same rule to 6 * 9. First add: 6 + 9 = 15. Then double it: 15 x 2 = 30.

The words ‘cats’ and ‘chase’ both appear in both sentences. Compare the two code groups: ‘ho mi lo ta’ and ‘ho su mi ka’. The codes common to both groups are ‘ho’ and ‘mi’, so these two codes belong to ‘cats’ and ‘chase’. The remaining codes in the first sentence, ‘lo’ and ‘ta’, must belong to the words that are not shared, which are ‘small’ and ‘mice’. So the answer is lo, ta.

In GOLD, each letter is shifted back by 1 place: G-1=F, O-1=N, L-1=K, D-1=C, giving FNKC, which matches. So the rule is: shift every letter back by 1 place. Apply the same rule to SILVER: S-1=R, I-1=H, L-1=K, V-1=U, E-1=D, R-1=Q. So the answer is RHKUDQ.

In SMART, the first letter S is moved to the end, giving MARTS, which matches. So the rule is: move the first letter of the word to the end. Apply the same rule to CLEVER: moving the first letter C to the end gives LEVERC. So the answer is LEVERC.