Exponential Word Problems Quiz

What is the general form of an exponential growth or decay equation?

• y = mx + b

• y = a(1 + r)^t

• y = a(1 - r)^t

• y = ab^x

If a town's population is 1,000 and it grows at 3% per year, how many people will there be in 5 years?

• 1,150

• 1,300

• 1,159

• 1,200

How many years will it take for the town's population to reach 1,500 if it grows at 3% per year?

• 15 years

• 12.3 years

• 10.5 years

• 13.7 years

What is the half-life of a substance if it takes 50 years to reduce to half its original amount?

• 25 years

• 50 years

• 100 years

• 75 years

If you start with 12 grams of a substance, how much will be left after 75 years given a half-life of 50 years?

• 3 grams

• 4.24 grams

• 8 grams

• 6 grams

How long will it take for the substance to decay to 1 gram if its half-life is 50 years?

• 150 years

• 250 years

• 179.2 years

• 200 years

A car worth $45,000 depreciates at 20% per year. What will its value be in 5 years?

• $14,745.60

• $18,000

• $20,000

• $25,000

How many years will it take for the car to be worth $3,000 if it depreciates at 20% per year?

• 10 years

• 12.1 years

• 15 years

• 20 years

If a bacterium doubles every 3 hours, how many bacteria will there be in 2 days starting with 20 bacteria?

• 1 million

• 500,000

• 1.3 million

• 2 million

How long will it take for the bacteria to reach 1 million if they double every 3 hours?

• 50 hours

• 60 hours

• 46.8 hours

• 40 hours