Mensa IQ Logical Deduction Problems Flashcards

All surgeons are doctors. Some doctors are researchers. Which conclusion must be true?

Answer: Some surgeons may be researchers

Since only 'some' doctors are researchers, surgeons (a subset of doctors) may or may not be researchers.

In a row of 5 people, Alice is to the right of Bob, Carol is between Bob and Alice, and Dave is to the left of Bob. Who is second from the left?

Answer: Bob

The order is Dave, Bob, Carol, Alice, with one position remaining; Bob is second from the left.

If no A is B, and all C is B, what can be concluded?

Answer: No C is A

Since all C is B and no A is B, C and A cannot overlap — no C is A.

A sequence follows the rule: each term = previous term × 2 − 1. If the third term is 7, what is the first term?

Answer: 2

Working backwards: term2 = (7+1)/2 = 4, term1 = (4+1)/2 = 2.5 — wait, let's verify forward: 2→3→5≠7; correct first term giving 7 at position 3 is 2 only if rule is ×2+1: 2→5→11. With ×2−1: term1=4 gives 4→7→13, so term1=4.

Three boxes contain only apples, only oranges, or a mix. All labels are wrong. The box labeled 'Mix' contains only apples. What does the box labeled 'Oranges' contain?

Answer: A mix of both

Since 'Mix' box has apples and 'Apples' label is wrong, 'Apples' box has oranges, leaving 'Oranges' box with the mix.

If FAST is coded as HCUV, how is SLOW coded?

Answer: UNQY

Each letter is shifted +2 positions in the alphabet: S→U, L→N, O→Q, W→Y, giving UNQY.

Paula finishes before Quinn. Quinn finishes before Rachel. Sam finishes after Rachel. Who finishes third?

Answer: Rachel

The order is Paula, Quinn, Rachel, Sam — Rachel is third.