Question

You borrowed $25 from your friend. You paid him back in full after 6 months. He charged $2 for interest. What was the annual simple interest rate that he charged you? Use the formula: I = Prt.

Answer 1

Trina borrowed $460 from a friend. Her friend charged her 5% simple annual interest.Let's solve how much will Trina owe her friend in total after 3 years? Use the simple interest formula to solve.

I = prt

I = (460)(0.05)(3)

I = 460 * 0.05 = 23

I = 23 * 3 years = 69 dollars is the interest.

Trina must pay her friend a total of $460 + 69 = 529.

Explanation:

Answer 2

`\bf \qquad \textit{Simple Interest Earned}\\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\to &\$2\\ P=\textit{original amount}\to& \$25\\ r=rate \\ t=years\to &(1)/(2) \end{cases}`

bearing in mind, "t" is in years, 6months is just 1/2 year

solve for "r", you'd get a decimal amount, multiply times 100, to get the percentage form