Exponential Growth & Decay

The amount of pain reliever medicine that is in the body after taking 75mg decreases at a rate of 3.25%. About how many milligrams are left in the body after 3 hours?

• 68

• 70

• 65

• 64

Steven is 42 inches tall. On average he grows at a rate of 5.5% each year. How tall will Steven be in 3 years?

• about 50 inches

• about 47 inches

• about 51 inches

• about 44 inces

The population of Michigan is 2.5 million people and grows at a rate of 3.5% every year. What will the population of michigan be in 10 years?

• about 3.5 million people

• about 4 million people

• about 3 million people

• 4.5 million people

It is estimated that the population of the world is increasing at an average annual rate of 1.3%. The population was about 6,472,416,997 in the year 2005. Use the model to estimate the current population.

• about 7.8 billion

• about 6.8 billion

• about 7 billion

• about 7.4 billion

How much of a radioactive kind of radium will be left after 8 days if the half-life is 4 days and you start with 48 grams?

• 12 grams

• 14 grams

• 24 grams

• 22 grams

The local newspaper in Arcadia, CA. has seen its subscriptions go down by 5% each year. The paper currently has 25,000 subscribers. How many subscribers will the paper have in 9 years?

• About 15757

• About 16755

• About 14852

• About 14975

Tara is playing a video game in which she establishes and builds up a city. The population of this city is currently 100,000 people, a number that increases by 10% every year. What will the population be in 6 years?

• About 177156

• About 178452

• About 179548

• About 176156

The half-life of a radioactive kind of antimony is 60 days. If you start with 160 grams of it, how much will be left after 180 days?

• 20 grams

• 22 grams

• 24 grams

• 18 grams

Winchester High School has student elections every year. Lately, the school has seen a 10% decrease in voting from election to election. If 662 students voted this year, how many will be expected to vote 5 years from now?

• About 391

• About 386

• About 401

• About 399

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates (loses value) at a rate of 5%. What will its approximate value be at the end of the fourth year?

• About $28507

• About $27699

• About $29517

• About $27907