Modeling Real-Life Exponential Decay Scenarios

A bacteria culture starts with 500 bacteria and decreases by 20% every hour. Write an equation to model the number of bacteria after t hours. How many bacteria will remain after 3 hours?

• 256

• 300

• 400

• 512

Tags

CCSS.HSF-LE.A.1C

A car's value decreases by 15% each year. If the car is initially worth $20,000, write an equation to represent its value after t years. What will the car be worth after 4 years?

• $8,500.75

• $12,000.00

• $15,000.00

• $10,440.13

Tags

CCSS.HSF.BF.A.2

A radioactive substance has a half-life of 5 years. If you start with 80 grams, write an equation to model the amount remaining after t years. How much will remain after 15 years?

• 40 grams

• 10 grams

• 20 grams

• 5 grams

Tags

CCSS.HSF.LE.A.4

A tree's height decreases by 10% each year due to disease. If the tree is currently 150 cm tall, write an equation to model its height after t years. What will the height be after 2 years?

• 121.5 cm

• 90 cm

• 135 cm

• 100 cm

Tags

CCSS.HSF-LE.A.1C

A population of fish in a lake decreases by 25% each year due to overfishing. If there are initially 1,200 fish, write an equation to model the population after t years. How many fish will be left after 3 years?

• 506

• 800

• 300

• 900

Tags

CCSS.HSF-LE.A.1C

A certain type of mold doubles in size every 3 days. If you start with 10 grams, write an equation to model the amount of mold after t days. How much will there be after 12 days?

• 80 grams

• 160 grams

• 120 grams

• 200 grams

A smartphone loses 30% of its value each year. If it was purchased for $800, write an equation to represent its value after t years. What will the value be after 2 years?

• 560

• 392

• 480

• 640

Tags

CCSS.HSF-LE.A.1C

A certain chemical decays at a rate of 5% per hour. If you start with 200 mg, write an equation to model the amount remaining after t hours. How much will remain after 6 hours?

• 130 mg

• 147.63 mg

• 150 mg

• 200 mg

Tags

CCSS.HSF-LE.A.1C

A population of rabbits decreases by 40% each year due to habitat loss. If there are initially 500 rabbits, write an equation to model the population after t years. How many rabbits will be left after 2 years?

• 300 rabbits

• 250 rabbits

• 180 rabbits

• 400 rabbits

Tags

CCSS.HSF-LE.A.1C

A savings account earns 4% interest compounded annually. If you start with $1,000, write an equation to model the amount in the account after t years. How much will be in the account after 5 years?

• 1500.00

• 1000.00

• 1216.65

• 2000.00