Codebusters Test Codebusters Logical Puzzles and Riddles 2

Question 1

In a cryptarithmetic puzzle, SEND + MORE = MONEY. What digit does M represent?

Accepted Answer

1

Answer

M = 1 because MONEY is a 5-digit sum of two 4-digit numbers, so the carry into the ten-thousands place can only be 1.

Question 2

A self-referential sentence reads: 'This sentence has ___ letters.' Which number correctly completes it?

Accepted Answer

30

Answer

Writing out 'thirty' gives exactly 30 letters in the full sentence, making it self-referentially true.

Question 3

If A=1, B=2, ... Z=26 in a simple substitution, what is the product of the values of the letters in 'CAB'?

Accepted Answer

6

Answer

C=3, A=1, B=2; 3×1×2 = 6.

Question 4

Three logicians (A, B, C) each see the others' hat colors but not their own. A says 'I don't know.' B says 'I don't know.' C immediately says 'I know.' What logical principle does C use?

Accepted Answer

Common knowledge elimination

Answer

C uses common knowledge elimination: A's and B's ignorance rules out scenarios where one color is unique, letting C deduce their own hat.

Question 5

A number is encoded so that each digit D becomes (D + 5) mod 10. What does encoded digit 3 decode to?

Accepted Answer

8

Answer

To decode, reverse the encoding: (3 − 5 + 10) mod 10 = 8.

Codebusters Test Practice Test

Codebusters Test Practice Test

Codebusters Test Codebusters Logical Puzzles and Riddles 2