Exponential graphs — Basic example

Exponential model word problem: bacteria growth (video) | Khan Academy

Solve the following problem involving exponential growth of bacteria colonies.Suppose that the concentration of a bacteria sample is 100,000 bacteria per milliliter. If the concentration doubles every 3 hours, how long will it take for the concentration to reach320,000 bacteria per milliliter?It will take about hour(s) for the concentration to reach 320,000 bacteria per milliliter.(Do not round until the final answer. Then round to the nearest tenth as needed.)