Exponential Growth and Decay

The number of mosquitoes at the beginning of the summer was 4,000. The population of mosquitoes is expected to grow at a rate of 25% a month. How many mosquitoes will there be after 4 months?

• 9766
• 9006
• 9765
• 5433

Classify the model as Exponential GROWTH or DECAY.
A=10(1.01)³

• Growth
• Decay

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

• Growth
• Decay

A 78 gram sample of Uranium loses half of its mass each year.  How much is left after 6 years?

• 13 grams
• 6.5 grams
• 1.22 grams
• 592.31 grams

James' 70 in. giant peach doubles in size every week. Write an expression that would represent how big the peach is after 5 weeks.

• 70(2)³⁵
• 70(2)⁵
• 2(70)⁵
• 5(70)²

The value of a painting is $12,000 in 1990 and increases by 8% of its value each year.  Write and evaluate an expression to estimate the paintings value in 2005.

• 1.08(12,000)^t = $36,000
• 12,000(1.08)^t = $38, 066
• 12,000(0.5)^t = $10,000
• 12,000(0.92)^t = $40,000

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

A population of fish starts at 8,000 and decreases by 6% per year. What is the population of fish after 10 years?

• 14327
• 4309
• 839
• 7680

Which of the following functions shows an initial amount of $15 and an increase of 35% each year?

• y = 15(35)^x
• y = 15(1.35)^x
• y = 15(0.35)^x
• y = 35(1.15)^x

Give the value of the growth factor:
y = 35(1.075)^x

• 35
• 0.075
• 7.5%
• 1.075