Approximately 9 out of 10 smokers began smoking before the age of 21. in a group of 400 smokers, about how many of them started before they reached their 21st birthday?

Acolony contains 1500 bacteria. the population increases at a rate of 115% each hour. if x represents the number of hours elapsed, which function represents the scenario? f(x) = 1500(1.15)" f(x) = 1500(115) f(x) = 1500(2.15) f(x) = 1500(215)