Skip to main content
Mathematics LibreTexts

6.14.3: Formula Review

  • Page ID
    129589
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)

    Formula Review

    6.1 Understanding Percent

    part \(=\) percent \(x\) total

    6.2 Discounts, Markups, and Sales Tax

    discount \(=\) percent discount \(\times\) original price

    sale price \(=\) original price - discount

    sale price \(=\) original price - percent discount \(\times\) original price \(=\) original price \(\times(1-\) percent discount \()\)

    markup \(=\) percent markup \(\times\) cost

    retail price \(=\) cost + markup

    retail price \(=\) cost + percent markup \(\times\) cost \(=\) cost \(\times(1+\) percent markup \()\)

    sales tax \(=\) purchase price \(\times\) tax rate

    Total price \(=\) purchase price + purchase price \(\times\) tax rate \(=\) purchase price \(\times(1+\) tax rate \()\)

    6.3 Simple Interest

    \(\begin{array}{l}I=P \times r \times t \\ T=P+I \\ T=P+P \times r \times t \\ I=P \times \dfrac{r}{365} \times t \\ F V=P+I=P+P \times r \times t \\ A=P \times \dfrac{r \times(1+r)^t}{(1+r)^t-1} \\ P V=\dfrac{F V}{(1+r t)}\end{array}\)

    6.4 Compound Interest

    \(\begin{array}{l}A=P\left(1+\dfrac{r}{n}\right)^{n t} \\ P V=\dfrac{A}{\left(1+\dfrac{r}{n}\right)^{n \times t}} \\ Y=\left(1+\dfrac{r}{n}\right)^n-1\end{array}\)

    6.6 Methods of Savings

    \(\begin{array}{l}A=P\left(1+\dfrac{r}{n}\right)^{n t} \\ \mathrm{ROI}=\dfrac{F V-P}{P} \\ F V=p m t \times \dfrac{(1+r / n)^{n \times t}-1}{r / n} \\ p m t=\dfrac{F V \times(r / n)}{(1+r / n)^{n \times t}-1}\end{array}\)

    6.7 Investments

    \(\begin{array}{l}\text { annual return }=\left(\dfrac{F V}{P}\right)^{\left(\dfrac{1}{t}\right)}-1 \\ \mathrm{P} / \mathrm{E}=\dfrac{\text { Share Price }}{\text { Dividend }} \\ \mathrm{Yld} \%=\dfrac{\text { Annual Dividend }}{\text { Share Price }} \times 100 \%\end{array}\)

    6.8 The Basics of Loans

    \(\begin{array}{l}I=P \times \dfrac{r}{n} \\ p m t=\dfrac{P \times(r / n) \times(1+r / n)^{n \times t}}{(1+r / n)^{n \times t}-1}\end{array}\)

    6.9 Understanding Student Loans

    funding gap = total cost - all aid

    \(\begin{array}{l}A=P\left(1+\frac{r}{n}\right)^{n t} \\ p m t=\frac{P \times(r / n) \times(1+r / n)^{n \times t}}{(1+r / n)^{n \times t}-1}\end{array}\)

    discretionary income \(=\) gross income \(-1.5 \times\) poverty guideline

    6.10 Credit Cards

    \(I=\dfrac{\mathrm{ADB} \times r \times d}{365}\)

    6.11 Buying or Leasing a Car

    \(\begin{array}{l}p m t=\dfrac{P \times(r / n) \times(1+r / n)^{n \times t}}{(1+r / n)^{n \times t}-1} \\ \mathrm{MD}=\dfrac{P-R}{n} \\ \mathrm{APR}=2400 \times \mathrm{MF} \\ \mathrm{MF}=\mathrm{APR} / 2,400 \\ P M T=\dfrac{(P-R)}{n}+(P+R) \times \mathrm{MF}\end{array}\)

    6.12 Renting and Home Ownership

    \(\begin{array}{l}p m t=\dfrac{P \times(r / 12) \times(1+r / 12)^{12 \times t}}{(1+r / 12)^{12 \times t}-1} \\ T=p m t \times 12 \times t \\ \mathrm{CoF}=T-P\end{array}\)


    This page titled 6.14.3: Formula Review is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by OpenStax via source content that was edited to the style and standards of the LibreTexts platform.

    • Was this article helpful?