Riddle:
You have a 4 minute sand clock and a 7 minute sand clock, you need to measure 9 minutes while using both of them. What's your first move?
(The 'Google Riddles' are interview questions those who wish to get hired were asked).
Show Hint
Hint:
To get to the right answer, you must turn them over first together, so when the 4 minute clock is done you start over
Show Answer
Answer:
Turn them over together. Then, the 4 minute one is done you immediately flip it over. The rest of the time until 7 runs out is exactly 3 minutes.