Mechatronics - Puzzle #9 - Sand Clock?

We have two sand clock, one have the capacity to show 4 minutes and other have the capacity to 
 show 7 minutes. 

Image result for 2 sand clock
By using the two sand clocks, you can use it single or combination of sand timers.



The target is to calculate time of 9 minutes.


4 comments:

  1. This comment has been removed by the author.

    ReplyDelete
  2. Start both the clock at same time
    2. When 4min sand clock finishes - we calculated 4 Mins.
    3. Invert the 4min sand clock
    4. By the time 7min sand clock would finish, and 1 min will be remaining in 4min sand clock- now we
    calculated total 7 Mins
    5. Now invert the 7min sand clock, and within 1 min the 4min sand clock would finish, now we calculated a total of 8 Mins.
    6. As soon as 4min sand clock finishes, invert the 7min sand glass.
    7. As the one minute in 7min finishes we would have calculated a total of 9 Mins.

    ReplyDelete
  3. 1.[(7:0),(4,0)], let's assume (7:0) as 7min hour glass where 7 is the time remaining in top of sand glass and 0 being the down of sand glass, similarly (4:0) is the 4min sand glass.
    2.[(3:4),(0,4)] - calculated 4 mins in total
    3.[(3:4),(4:0)] - inverted 4min sand glass
    4.[(0:7),(1:3)] - calculated 7 Mins in total
    5.[(7:0),(1:3)] - inverted 7min sand glass
    6.[(6:1),(0:4)] - calculated 8 Mins in total
    7.[(1:6),(0:4)] - inverted 7min sand glass
    8.[(0:7),(0:4)] - calculated 9 Mins in total

    The beauty of this problem is sum of all numbers in each individual step will always be 11

    ReplyDelete

Comments are welcome !