Quiz about Exponential Growth and Decay Factors

Question 1

If f(x) = 2x-9, what is f(3)?

Accepted Answer

-3

Answer

6

Answer

3

Answer

-6

Question 2

In an exponential function, what does the 'a' represent?

Accepted Answer

Y-INTERCEPT

Answer

SLOPE

Answer

RATE OF CHANGE

Answer

COMMON RATIO

Question 3

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

Accepted Answer

y=5000(0.7)^x

Answer

y=30(5000)^x

Answer

y=5000(1.3)^x

Answer

y=5000xx

Question 4

Which equation matches the graph?

Accepted Answer

y=2(2)x

Answer

y=2(1/2)x

Answer

y=2x

Answer

y=1/2(2)x

Question 5

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

Accepted Answer

70(2)5

Answer

70(2)35

Answer

2(70)5

Answer

5(70)2

Question 6

What is the y-intercept of the function?

Accepted Answer

3

Answer

2

Answer

1

Answer

-2

Question 7

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?

Accepted Answer

9766

Answer

9006

Answer

9765

Answer

5433

Question 8

Write an equation that models the following situation:
Samantha's hair was known to grow very rapidly. It began at a length of 6 in and grew at a rate of 14% a week.

Accepted Answer

y=6(1.14)^x

Answer

y=6(0.14)^x

Answer

y=6(1+14)^x

Answer

y=6(0.86)^x

Question 9

What type of function is y = 7(5/4)^x?

Accepted Answer

Exponential Growth

Answer

Exponential Decay

Answer

Linear

Answer

None of the above

Question 10

What is a, the starting term, for the function: f(x) = 300(1.16)^x?

Accepted Answer

300

Answer

1.16

Answer

.16

Answer

x

Question 11

What is b, the common ratio, for the function: f(x) = 300(1.16)^x?

Accepted Answer

1.16

Answer

300

Answer

.16

Answer

x

Question 12

What is a, the starting term, for the function: f(x) = 800(0.85)^x?

Accepted Answer

800

Answer

0.85

Answer

0.15

Answer

x

Question 13

A 78 gram sample of Uranium loses half of its mass each year.  What is the exponential equation?

Accepted Answer

y=78(0.5)^x

Answer

y=78(1.5)^x

Answer

y=78(2)x

Question 14

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

Accepted Answer

1.22 grams

Answer

13 grams

Answer

6.5 grams

Answer

592.31 grams

Question 15

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

Accepted Answer

y = 15(1.35)^x

Answer

y = 15(35)^x

Answer

y = 15(0.35)^x

Answer

y = 35(1.15)^x

Question 16

Twenty years ago, Mr. Davis purchased his home for $160,000. Since then, the value of the home has increased about 5% per year. How much is the home worth today?

Accepted Answer

$424,527.63

Answer

$176,783.29

Answer

$57,357.75

Answer

$532,041,076.80

Question 17

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

Accepted Answer

4309

Answer

14327

Answer

839

Answer

7680

Question 18

Since January 1980, the population of the city of Brownville has grown according to the mathematical model y=720,500(1.022)^x, where x is the number of years since January 1980. What is the percentage increase of the population annually?

Accepted Answer

2.2%

Answer

720,500%

Answer

102.2%

Answer

22%

Question 19

Since January 1980, the population of the city of Brownville has grown according to the mathematical model y=720,500(1.022)^x, where x is the number of years since January 1980. What is the was the population of Brownville in 1980?

Accepted Answer

720,500 people

Answer

102.2 people

Answer

1.022 people

Answer

1022 people

Question 20

A population of 2200 beetles is too large to sustain and decreases in population each month at a rate of 5%. How would you write your growth rate, b?

Accepted Answer

.95

Answer

-5

Answer

-.05

Answer

.05

Question 21

A population of 2200 beetles is too large to sustain and decreases in population each month at a rate of 5%. Approximately what would the population be after a year and a half?

Accepted Answer

874 beetles

Answer

5295 beetles

Answer

8.38E-21 beetles

Answer

2037 beetles

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