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 the nearest whole number.

If the intial count was 100,000 bacteria, after one hour 90% decrease => 10 % stands => 100,000*0.1 bacetria. After two hours 90% decrease => 10% stands => 100,000*0.1^2. After three hours, they stand 100,000 * 0.1^3. After four hours, 100,000*0.1^4 and after five hours 100,000*0.1^5 = 1 bacteria. 1 bacteria. If the inital count is different you just have to muliply the inicial count time (0.1^n) to get the number of bacteria after n hours, and if the number of hours is 5, then the factor is (0.1^5).