Exponential Word Problems Half the Life

A city doubles its size every 64 years. If the population is currently 225,000, what will the population be in 128 years?

• The population will be 225,000.

• The population will be 450,000.

• The population will be 900,000.

• The population will be 1,800,000.

You have 30,016 grams of radioactive kind of rubidium. How much will be left after 54 minutes if its half-life is 18 minutes?

• 15,008 grams.

• 7,504 grams

• 3,752 grams.

• 1,876 grams.

Due to its weakening steel industry, Canalave Town has been experiencing a population decline of 10% every year. The current population is 74,000 people. Assuming the trend continues, which equation projects the population in x years?

• y = 74,000 (0.10)^x

• y = 74,000 (0.90)^x

• y = 74,000 (1.10)^x

• y = 74,000 (1.90)^x

If 10 mg of iodine 131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

• 25mg

• 25g

• 10g

• 10mg

You buy a new computer for $2100. The computer decreases by 50% annually. How much is it worth after 2 years.

• $225

• $325

• $425

• $525

Classify the model as Exponential GROWTH or DECAY.
A=1200(.85)⁶

• Growth

• Decay

The equation that models how much Acetaminophen is in his body is y=400(0.86)^x Calculate how much medicine is left after 10 hours

• 400 milligrams

• 344 milligrams

• 89 milligrams

• 11 milligrams

The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?

• 100.0g

• 50.0g

• 12.5g

• 8.5g

The half life of iodine-131 is 8.040 days. What percentage of an iodine-131 sample will remain after 40.20 days?

• 312.5%

• 31.25%

• .3125%

• 3.125%

Suppose a culture of bacteria begins with 5000 cells and dies by 30% each year. Write an equation that represents this situation.

• y=5000(0.7)^x

• y=30(5000)^x

• y=5000(1.3)^x

• y=5000x^x