Question

Diana invested $3000 in a savings account for 3 years. She earned $450 in interest over that time period. What interest rate did she earn? Use the formula I=Prt to find your answer, where I is interest, P is principal, r is rate and t is time. Enter your solution in decimal form rounded to the nearest hundredth. For example, if your solution is 12%, you would enter 0.12.

Answer 1

$\bf \qquad \textit{Simple Interest Earned}\\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\to &\ 450\\ P=\textit{original amount deposited}\to& \ 3000\\ r=rate\to r\%\to \frac{r}{100}\\ t=years\to &3 \end{cases} \\\\\\ 450=3000\cdot r\cdot 3\implies \cfrac{450}{3\cdot 3000}=r\implies \cfrac{1}{20}=r \\\\\\ r\%\implies \cfrac{1}{20}\cdot 100\implies r=\stackrel{\%}{5}$

Answer 2

Answer:

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Step-by-step explanation: