Answer:
Six seconds for each bacteria to become 4
Explanation:
1 bacteria at time 0
after 6 seconds, 1 bacteria multiplies into 4 and become 4 bacteria
after other 6 seconds, 4 bacteria multiplied into 4 becomes 16
after 6 more seconds, 16 bacteria are multiplied into 4 becomes 64
after 30 seconds, 256 bacteria will be 1024