Recently, a small village, in Tamilnadu where only male shepherd reside with four sheep each, was devastated by Tsunami waves. Therefore 8 persons and 47 sheep were found to be dead and the person who luckily survived, left the village with one sheep each since 21 sheep were too injured to move so have left on their on luck, in the village. The number of sheep which were earlier in the village was :

Explanation:-

Let there be x people in the village so, then 4x sheep must be there.
No, number of person leaving the village,
= (x - 8) [as 8 person died in Tsunami]
And the number of sheep to be carried with the survived people,
4x - (47 + 21) = x - 8. [Here we are equating No of alive sheep and no. of alive person. As 1 person has 4 sheep means 1 person = 4 sheep.]
Or, 3x = 60
Or, x = 20
Or, 4x = 80
Hence,
80 sheep