Exponential Functions Predictions

Pick the equation that is exponential decay

• y=2000(0.88)

• y=0.5(1.88)

A scientist studied bacteria. She placed 5 bacteria in a dish. The population of the bacteria doubles every 12 hours.
Which equation can be used to determine the number of bacteria, y, present after x days?

• y = 5(2)^x

• y = 5(10)^x

• y = 5(2)^2x

• y = 5(10)^2x

The function f(x) = (4)^x was replaced with f(x) + k, resulting in the graph shown.  What is the value of k?

• 0

• 1

• -1

• 2

Every 10 years, the Census counts how many people are living in every town in the US.  
- The 2010 Census showed that 2000 people lived in Fruitland, and 5000 people lived in Batcave.
- The population of Fruitland is predicted to double every 5 years.
- The population of Batcave is predicted to increase by 1000 every 5 years.
*If the predictions are true, what will be the first Census year that Fruitland's population will be larger than Batcave?

• 2015

• 2020

• 2002

• 2001

Joey and Roger are playing a game.
- Joey and Roger each started with 50 points.
- At the end of each turn, Joey's points double.
- At the end of each turn, Roger's points increase by 200.
At the start of which turn will Joey have more points than Roger?

• 2

• 3

• 4

• 5

A club began with 4 members.  Each month, each member brought 2 new members.  Which function can be used to determine the number of members x months after the club began?

• f(x) = 2x + 4

• f(x) = 4x + 2

• f(x) = 4(2)^x

• f(x) = 4(3)^x

What is the equation of this table?

• y=512(1/4)^x

• y=32(4)^x

• y=32(1/4)^x

• y=512(4)^x

Suppose the population of a species of insects doubles every year. There are 1600 insects initially. The function for the scenario would be?

Given this table, write a power model for the data.

Write the exponential equation that represents the given graph.