A particular pain relieving medicine has a decay rate of 23 % per hour. A patient was given a dose of the medicine 8 hours ago and there is currently 72 milligrams of the medicine in the patients bloodstream.

What was the original dose of the medicine? __________ milligrams

How long will the patient need to wait for there to be less than 25 % of the original dose of the medicine left in their bloodstream?Express your answer as a decimal to the nearest tenth of an hour. _________ hours

Bacteria X has a growth rate of 170 % per hour. Some amount of bacteria X are accidentally introduced into some fruit salad. Two hours after contamination, there were 20,000 bacteria X in the fruit salad. Find the initial number of bacteria X introduced into the fruit salad: __________ bacteria Estimate the number of bacteria in the food 3 hours after contamination. ____________ bacteria

A city had a population of 8,177 at the begining of 1946 and has been growing at 8.5% per year since then.

Note: EX 9.3 (a) Find the size of the city at the beginning of 1973. Answer:

(b) Duringwhat yearwill the population of the city reach 20,519,507 ? Answer:

Goods costing $23.47 at the beginning of the year 1958 cost $248.98 at the beginning of the year 1995. Find the average annual inflation rate over this time period.Express your answer the nearest thousandth of a percent.

NOTE: EX 9.5 Answer:

A bacteria has a doubling period of 8 days. If there are 3050 bacteria present now, how many will there be in 40 days? First we must find the daily growth rate(Don't round up, keep all the decimal places). The growth rate is ________. Then we use this rate to answer the question. There will be________bacteria.

A particular radioactive isotope decays from 250 milligrams (mg) to 220 mg in 6 days. Find the half life of the isotope. Hint: Find the rate first. The half life of the isotope is the half value of 250 mg then solve for x. Your answer is _______days.

A town in the mid west has been experiencing a steady population decline of 3.75 % per year for the past decade. If there were 49050 residents in the year 2011 and the trend continues, what will the population be in the year 2034? Round UP your answer to the nearest person.

_________ people