STAAR Algebra I Exponential Functions and Equations. Practice it free.

A charity drive starts with $80$ donors. Each day after the first day, a model estimates that the number of donors increases by $25\%$ of the number of donors the previous day. Which equation defines this model, where $d(n)$ is the estimated number of donors $n$ days after the drive begins?

The function $D$ is defined by $D(t) = 1{,}500(0.6)^{t/5}$. The function $D$ models the amount of a drug, in micrograms, in a patient's bloodstream, where $t$ is the number of hours after a dose is given. Which statement best describes what the factor $0.6$ represents in this model?

You invest $\text{\char36}2000$ at $5\%$ annual interest for $1$ year. What is the total?

The function $m$ is defined by $m(d) = 500(0.92)^{d}$. The function models the mass, in grams, of a sample $d$ days after a reaction begins. Which statement is the best interpretation of the decay factor $0.92$ in this context?

The given equation represents the number of seats $n$ filled, where $r$ represents the number of rows occupied.

$n = 18r$

Which of the following is the best interpretation of $18$ in this context?

A school play has a total ticket revenue of $\text{\char36}84$ from adult tickets and child tickets. The situation is modeled by $5a + 3c = 84$, where $a$ is the number of adult tickets sold and $c$ is the number of child tickets sold. Which is the best interpretation of the number $3$ in this equation?

Temperature, in $^\circ$F, after $x$ hours past noon:
$\begin{array}{c|c} x & f(x) \\ \hline 2 & 62 \\ 4 & 56 \\ 6 & 50 \\ 8 & 44 \end{array}$
The temperature is $f(x)=mx+68\textsf{.}$ What is $m\textsf{?}$

The table shows values of a linear function $r\textsf{.}$
$\begin{array}{c|cccc} x & 1 & 2 & 3 & 4 \\ \hline r(x) & 9 & 5 & 1 & -3 \end{array}$
Which of the following is $r(x)\textsf{?}$