 
<translate> Ugbu a, m ga-abụ 4 * 4 = afọ iri na isii, ebe ọ bụ na m ji okpukpu anọ karịa afọ anọ nke Billy. N'ihi ya, iji chọpụta afọ ole m dị mgbe a mụrụ Billy, anyị ga-ewepụ afọ anọ Billy dị site n'afọ ole m dị, nke pụtara na m dị afọ iri na isii - 4 = afọ iri na abụọ. Ya mere, azịza ikpeazụ bụ 12. <eng> I would currently be 4 * 4 = 16 years old, since I'm 4 times older than Billy's age of 4. Therefore, in order to find my age at Billy's birth we'd simply subtract Billy's age of 4 from my age, meaning I was 16 - 4 = 12 years old. So the final answer is 12. 