Brain Teasers and Lateral Thinking Puzzles

Both 1kg cotton and 1kg iron have the same mass (1 kilogram). The confusion often comes from the difference in density - cotton is much less dense than iron, so 1kg of cotton occupies much more volume than 1kg of iron. However, 'heavier' refers to weight/mass, which is equal in this case.

This is a classic riddle. All 12 months have at least 28 days. February has exactly 28 days in non-leap years, but the other 11 months also have 28 days as part of their 30 or 31 days.

When spelling numbers from 1 to 100 (One, Two, Three... Ninety-nine, One hundred), none of them contain the letter 'A'. The letter 'A' first appears in 'Thousand'.

Electric trains run on electricity and do not produce smoke like steam or diesel locomotives. The wind direction is irrelevant because there is no smoke to blow. Options A, B, and C all assume smoke exists, which is the trap.