Interview Q&A / Aptitude

1. The minute hand of a clock overtakes the hour hand every 64 minutes of correct time. How much does the clock gain or lose in a day?

   It gains 32 8/11 minutes a day. In a correct clock the hands meet every 65 5/11 minutes. Here they meet after only 64 real minutes, so the clock runs fast: it shows 65 5/11 minutes in 64 real minutes, gaining 16/11 minutes every 64 minutes, which is 360/11 = 32 8/11 minutes in 1,440 minutes.

   AdvancedQuick answer1 min read
2. What day of the week was 15 August 1947?

   Friday. Count odd days (days beyond complete weeks): 1,900 years give 1 odd day, 1901 to 1946 give 46 + 11 leap days = 57, which is 1, and 1 January to 15 August 1947 gives 227 days, which is 3. Total 5 odd days, and 5 corresponds to Friday.

   AdvancedQuick answer1 min read