Question

Dr. Jimenez found that after applying an antibiotic to bacteria,he observed only 90% of the bacteria left in the culture dish each hour.If the initial bacteria count was 100, what was the bacteria count after 5 hours ? Round to he nearest whole number.

Answer 1

59 (59.049)
(0.9^5) × 100
0.9 is the percent (90%), 5 is the amount of hours, and 100 is the starting amount.
100×0.9×0.9×0.9×0.9×0.9 is easier to understand, but 0.9^5 is much shorter.