Exponential Growth/Decay

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

What is the balance of $6000 compounded annually at a rate of 4% for 10 years?

• $8,881.47
• $7,432.93
• $8,400
• $6,500

Jame's 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 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

The attendance at the art museum at the New Year’s opening was 250 people. The attendance has been increasing at a rate of 3% each month. How many people will attend by the end of a year?

• 356
• 265
• 5825
• 1329

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

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

Daniel’s Print Shop purchased a new printer for $35,000. Each year it depreciates at a rate of 5%. How much will the printer be worth in 8 years?

• $23,219.72
• $136.72
• $51,710.94
• $16,710.94

Caiden earned $475 from mowing lawns last summer.He deposited this money in an account that pays an interest rate of 3.8% compounded annually. What will be his balance after 15 years?

• $827.52

• $831.10

• $839.45

• $846.80

Mark took a loan out for $25,690 to purchase a truck. At an interest rate of 5.2% compounded monthly, how much total will he have paid after 5 years?

• $33,299.42

• $33,672.68

• $34,157.04

• $34,710.88