Growth and Decay Quiz

A business paid [Dollar] 300 to rent a piece of office equipment for one year. The rent was then increased by 10% each year thereafter. How much will the company pay for the first three years it rents the equipment?

• 920

• 960

• 990

• 993

A scientist places an initial population of 3.5×104 bacteria on a plate containing glucose. She knows that this type of bacteria, when supplied with abundant glucose, can double every two hours. When she checks on the bacteria at the same time the next day, approximately how many should she expect to find, assuming the bacteria do not run out of glucose to eat?

• 9.27×1012

• 9.27×1014

• 9.35×1014

• 9.35×1016

A special lizard population is in danger of becoming extinct. In 1920 , the blue speckled lizard population contained 3.78×107 individuals. It has decreased by 2% every year since. If the rate of decay continues in this fashion, in what year will the population be roughly 6.25×106 ?

• 2008

• 2010

• 2012

• 2014

Tina works at a university where the student population has seen growth over the last 50 years. In 1950 the student population was 500 and on average, every year it increases by 4%. If the university continued to grow in this way, how many students were in the class of 2015 ?

• 6732

• 6740

• 6774

• 6791

Connor invests a sum of money at an interest rate of 3% per year compounded annually. The value of the investment, y, after n years can be calculated using the equation y=A(x)n. If Connor invests $250 and wants to calculate the value of his investment after 10 years, assurning no further deposits or withdrawals, which of the following equations should he use?

• y=250(0.97)10

• 
  y=(250×0.03)10

• y=250(0.03)10

• 
  y=250(1.03)10

The number of bacteria in a colony is estimated over the course of 9 days, as shown in the table below. Which of the following best describes the relationship between time and the estimated number of bacteria over these 9 days?

• Linear decrease

• Linear increase

• Exponential decay

• Exponential growth

The number of cells in a certain lab experiment triples every hour. If there are 5 cells in the culture initially, then what is the number of cells in the culture after 4 hours?

• 15

• 20

• 135

• 1.875

Of the following four types of savings account plans, which option would yield exponential growth of the money in the account?

• Each successive year, 2% of the initial savings is added to the value of the account

• Each successive year, 1.5% of the initial savings and 100 dollars is added to the value of the account.

• Each successive year, 1% of the current value is added to the value of the account

• Each successive year, [Dollar]100 is added to the value of the accoun

The breakdown of a 500-milligram sample of a chemical compound in the bloodstream is represented by the function p(n)=500(0.8)n, where p(n) represents the number of milligrams of the compound that remains at the end of n hours. Which of the following is true? I. The amount of the compound present is decreasing by a constant amount. II. Each hour the compound gets reduced by 20% of the amount present at the beginning of that hour. III. Each hour the compound gets reduced by 80% of 500

• I only

• II only

• 
  I and III only

• II and III only

A radioactive isotope has decayed to a size of 202 kilograms over the last 20 years. If the isotope has a half life of 40 years, which of the following is equivalent to, the initial mass of the isotope 20 years prior?

• 
  I=202(21​)2

• I=101(21​)2

• I=1012​ -

• 
  I=2022