 
 <translate> First find how many zombies there were one day ago: 480 zombies / 2 = 240 zombies. Then find how many zombies there were two days ago: 240 zombies / 2 = 120 zombies. Then find the number of zombies there were three days ago: 120 zombies / 2 = 60 zombies. Then find the number of zombies there were four days ago: 60 zombies / 2 = 30 zombies, which is less than 50, so there were less than 50 zombies 4 days ago. The final answer: 4. <hau> Da farko ka gano yawan zombies da suka kasance a rana daya da ta gabata: 480 zombies / 2 = 240 zombies. Sannan ka gano yawan zombies da suka kasance kwana biyu da suka gabata: 240 zombies / 2 = 120 zombies. Sa'an nan sami yawan zombies akwai kwanaki uku da suka wuce: 120 zombies / 2 = 60 zombies. Sa'an nan sami yawan zombies akwai kwanaki hudu da suka wuce: 60 zombies / 2 = 30 zombies, wanda yake shi ne kasa da 50, don haka akwai kasa da 50 zombies kwanaki 4 da suka wuce. Amsar ƙarshe: 4. 