In a recreational activity, you are given four different jars of 2 litres, 4 litres, 6 litres and 8 litres respectively with an unlimited water supply.
Then you are asked to measure exactly 5 litres of water using them.
How will you do it?
If we have to measure precisely, it is impossible.
Because we are asked to measure odd number of litres whereas all the jars we have can contain only even litres of water.