Use the scenario to answer questions 18-20. Express your answers as a You draw four cards from a standard deck of 52 playing cards. I can
fraction
card is returned after being drawn,
18. What is the probability of choosing 4 hearts?
19. What is the probability of choosing 3 aces?
20. What is the probability of choosing four red cards?

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount

The biologist has a second culture to examine. she knows that the population of the culture doubles every 15 minutes. after 1 hour and 15 minutes, her assistant found that 80,000 bacteria were present. a) what was the size of the initial population? b) predict the size of the culture at t=3 hours. what was the size of the population at 40 minutes? explain and justify your answers. c) create a graph of the population as a function of time. find an equation that can be used to predict the size of the population at any time t. d) examine the rate at which the bacteria culture is growing. how fast is the culture growing after 1 hour? after 1.5 hours? after 2 hours? use a time interval of h = 0.01 hours to estimate these rates. interpret these rates in terms of the context of the problem situation. how do these three rates compare?