A clock is set right at 12 noon on Monday. It losses 1/2% on the correct time in the first week but gains 1/4 on the true time during the second week. The time shown on Monday after two weeks will be

Explanation:-

Time lost over two weeks = 25% a week time(given that 1/2% clock loses in first week and in the second week it gains 1/4% on true time)
A week = 168 hours
Hence, clock lost = 0.42 hours = 25.2 minutes or 25 minute 12 seconds.
Thus, correct time = 12:25:12.