Writing and Interpreting Exponential Functions STAAR Review

A bank account earning annual compound interest was opened, and no additional deposits or withdrawals were made after the initial deposit. The balance in the account after x years can be modeled by b(x) = 850(1.025)^x.

Which statement is the best interpretation of one of the values in this function?

• The initial balance decreases at a rate of 97.5% each year.

• The balance in the account increases at a rate of 2.5% each year.

• The initial balance of the account was $1,025.

• The balance in the account at the end of one year was $850.

Scientists are studying a bacteria sample. The function f(x) =245(1.12)^x gives the number of bacteria in the sample at the end of x days.

Which statement is the best interpretation of one of the values in this function?

• The initial number of bacteria is 12.

• The initial number of bacteria decreases at a rate of 88% each day.

• The number of bacteria increases at a rate of 12% each day.

• The number of bacteria at the end of day one is 245.

• The interest the savings account earned for the first year

• The annual interest rate of the savings account

• The number of years the savings account has earned interest

• The starting balance of the savings account

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The table represents some points on the graph of an exponential function.

Which function represents this relationship?

An exponential function is graphed on the grid. Which function is best represented by the graph?

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The table represents some points on the graph of an exponential function.

Which function represents the same relationship?

There are 1,024 players in a tennis tournament. In each round, half of the players are eliminated. Which function can be used to find the number of players remaining in the tournament at the end of x rounds?

In the year 1900, the total number of metric tons of copper produced in the world was 495,000. Each year since 1900, the total number of metric tons of copper produced has increased on average by about 3.25% over the amount produced the previous year.

What function models the total number of metric tons of copper produced in the year that is x years since 1900?

A particular type of cell doubles in number every hour. Which function can be used to find the number of cells present at the end of h hours if there are initially 4 of these cells?