 
 <translate> 4 hours is 4 * 60 = 240 minutes. If the doubling time is 20 minutes, then after 240 minutes, the number of bacteria would have doubled 240 / 20 = 12 times. Thus, starting with only 1 bacterial cell, after 4 hours, there will be 1 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 4,096 bacterial cells.
The final answer: 4096. <ibo> Awa anọ bụ 4 * 60 = nkeji 240. Ọ bụrụ na oge nke okpukpu abụọ bụ nkeji iri abụọ, mgbe ahụ mgbe nkeji 240 gasịrị, ọnụ ọgụgụ nke nje ga-amụba okpukpu abụọ 240 / 20 = ugboro iri na abụọ. N'ihi ya, malite na mkpụrụ ndụ nje 1 nanị, mgbe awa 4 gasịrị, a ga-enwe mkpụrụ ndụ nje 1 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 * 2 = 4,096. Azịza ikpeazụ ya bụ: 4096. 