Logical Reasoning and Puzzles Flashcards

If no birds are reptiles, and all parrots are birds, which statement must be true?

Answer: No parrots are reptiles

Since all parrots are birds and no birds are reptiles, it follows necessarily that no parrots are reptiles.

What is the missing term? ACE, BDF, CEG, ?

Answer: DFH

Each triplet shifts every letter by +1: A→B→C→D, C→D→E→F, E→F→G→H, so the answer is DFH.

Tom is older than Sam. Sam is older than Raj. Raj is older than Priya. Who is the youngest?

Answer: Priya

The chain Tom > Sam > Raj > Priya places Priya at the bottom as youngest.

A statement is made: 'If it rains, the ground is wet.' The ground is not wet. What can you conclude?

Answer: It is not raining

By contrapositive, 'not wet ground' implies 'it did not rain.'

Which figure completes the pattern? Each row contains a circle, triangle, and square. Row 3 has a circle and square. What is missing?

Answer: Triangle

Each row must contain exactly one of each shape; the missing shape in row 3 is a triangle.

A puzzle box has 3 dials each with digits 0–9. How many unique 3-digit combinations are possible (repetition allowed)?

Answer: 1000

Each dial has 10 choices independently, so 10×10×10=1000 total combinations.

Two candles of equal length are lit simultaneously. Candle A burns out in 3 hours; Candle B in 5 hours. After how many hours is Candle A half the length of Candle B?

Answer: 1.875 hours

At time t: A=(1−t/3), B=(1−t/5); set A=B/2 → 1−t/3=(1−t/5)/2 → t=15/8=1.875 hours.