A old farmer had 49 cows and 7 sons. Each cow was numbered from 1 to 49 by the farmer. The peculiarity of these cows was that each cow gave milk equal to its number. That is 1st cow gave 1 litre of milk, 2nd gave 2 litres. Once the farmer fell sick, he called his 7 sons and distributed the cows between them so that each one will get the same number of milk and same number of cows. Can you distribute the cows among the 7 sons.