Answer: After 13 (12) hours, there would be 6,500 bacteria across the culture.
Step-by-step explanation:
The bacteria grew by 500 each 4 hours, so to know how much there would be 13 hours later:
Simple, add 500 bacteria to every 4 hours until you reach 13 hours. 4 = 5.5k, 8 = 6k, 12 = 6.5k. Now, 12 is closer to 13 than anything we would've gotten if we kept going.
And there's your answer.
