Logical Reasoning Puzzles Flashcards

Five friends ran a race. Alice finished before Ben, but after Chloe. David finished before Eric, but after Ben. Who finished in fourth place?

Answer: David

The first clue, 'Alice finished before Ben, but after Chloe,' gives the order: Chloe, Alice, Ben. The second clue, 'David finished before Eric, but after Ben,' gives the order: Ben, David, Eric. Combining these two sequences gives the complete finishing order: Chloe (1st), Alice (2nd), Ben (3rd), David (4th), and Eric (5th). Therefore, David finished in fourth place.

Four children—Mark, Nina, Omar, and Pam—each own exactly one pet: a cat, a dog, a fish, or a bird. Use the following clues to determine who owns the dog: 1. Pam's pet can fly. 2. Mark's pet does not have fur. 3. Nina is allergic to cats.

Answer: Nina

From clue 1, Pam owns the bird. From clue 2, Mark's pet does not have fur; since the bird is taken, Mark must own the fish. From clue 3, Nina is allergic to cats, so she cannot own the cat. The only pets left are the dog and the cat. Since Nina cannot have the cat, she must own the dog. This leaves Omar with the cat.

On a strange planet, the following statements are true: All wimbles are zoodles. Some zoodles are flurgs. No flurgs are glonks. Which of the following statements must also be true?

Answer: Some zoodles are not glonks.

We know that some zoodles are flurgs, and we know that no flurgs are glonks. This means there is a specific group of zoodles (the ones that are also flurgs) that are definitely not glonks. Therefore, the statement 'Some zoodles are not glonks' must be true. We cannot be sure if the wimbles are part of the zoodles that are flurgs, so the other options are not guaranteed.

You meet two islanders, Alex and Ben. One always tells the truth, and the other always lies. Alex says, 'Ben and I are both liars.' Which of the following statements must be true?

Answer: Alex is the liar and Ben is the truth-teller.

Consider the possibilities for Alex. If Alex were the truth-teller, his statement ('Ben and I are both liars') would have to be true. But this is a contradiction, as the truth-teller cannot be a liar. Therefore, Alex must be the liar. If Alex is the liar, his statement must be false. The opposite of 'Ben and I are both liars' is 'at least one of us is not a liar.' Since we've established Alex is the liar, Ben must be the one who is not a liar, making him the truth-teller.

Five houses stand in a row, painted Red, Blue, Green, Yellow, and White. The Green house is to the right of the Yellow house. The Blue house is not at either end of the row. The Red house is exactly between the Green and the White houses. If the Yellow house is at the far left end, which house is in the middle?

Answer: White

Given the Yellow house is first (Position 1). The Blue house cannot be at an end (so not in 1 or 5). The Red house is between Green and White, forming a G-R-W or W-R-G block. The only arrangement that fits all rules is: Yellow, Blue, White, Red, Green. This places Yellow at the far left, Blue is not at an end, the G-R-W block is intact (with Blue in between), and Green is to the right of Yellow. In this order, the house in the middle (Position 3) is the White house.

A family has a father, a mother, a son, and a daughter. Their names are Pat, Sam, Lou, and Jo, not in order. You are given these clues: 1. Sam and Lou are of the same gender. 2. The daughter is the youngest member of the family. 3. Pat is older than Jo. Which of the following must be the two female members of the family?

Answer: Pat and Jo

The family has two males and two females. From clues 2 and 3, Pat is older than Jo, and the daughter is the youngest. This means Pat cannot be the daughter, so Jo must be the daughter. Since Jo is female, and clue 1 states Sam and Lou are the same gender, they cannot be female (otherwise, there would be three females: Jo, Sam, and Lou). Therefore, Sam and Lou must be the two males (father and son). This leaves Pat and Jo as the two females (mother and daughter).