Question

The formula for determining simple interest is i=prt, wherei is the interestp is the principalr is the interest rate as a decimal. For example, if the interest rate is 3%, then r = 0.03.t is the timeUnits must be consistent. If the unit for p is dollars, the unit for i is dollars and the unit for t is years, what must the units for r be?_______Solve this formula for r.r = ______5000 dollars are invested at a simple interest rate of 1 percent for 2 years. How much interest is earned, to the nearest cent?______ dollarsWhat is the interest rate, as a percent, that is necessary to earn 250 dollars in simple interest if 2000 dollars are invested for 3 years, to 1 decimal place?_____ % year

Answer 1

Kindly check below

1) Considering the formula:

$I=Prt$

We can solve for r, this way we get the rate in a straightforward way:

$\begin{gathered} I=Prt \\ \\ \frac{I}{Pt}=\frac{Prt}{Pt} \\ \\ \frac{I}{Pt}=r \\ \\ r=\frac{I}{Pt} \end{gathered}$

2) For the following parts, we're putting into practice:

$\begin{gathered} I=Prt \\ \\ I=5,000\times0.01\times2 \\ \\ I=100 \end{gathered}$

Note that we ought to write the percentage in decimal form.

3) Finally, let's write the following:

$\begin{gathered} r=\frac{I}{Pt} \\ \\ r=\frac{250}{2000\times3} \\ \\ r=\frac{1}{24} \\ \\ r\approx0.0417 \end{gathered}$

Thus, the interest rate is approximately 4.2%