You are given two hourglasses which can measure 11 minutes and 7 minutes (the sand
in each of the hourglasses takes that much time to run out). You don’t have access to any other clocks
and you cannot determine the amount of sand in each hourglass at an arbitrary time. You can claim
that you can measure a particular time interval t minutes if and only if you can specify a ‘start’ and
an ‘end’ time and the time interval in between these times equals t minutes. How many of the below
time intervals can be measured using the above definition?
