Question

Rajiv puts $2400 in a savings account.

One year later it is worth $2580

Work out the annual rate of interest.​

Answer 1

7.5%

Explanation:

Answer 2

`~~~~~~ \textit{Simple Interest Earned Amount} \\\\ A=P(1+rt)\qquad \begin{cases} A=\textit{accumulated amount}\dotfill & \$2580\\ P=\textit{original amount deposited}\dotfill & \$2400\\ r=rate\to r\%\to (r)/(100)\\ t=years\dotfill &1 \end{cases} \\\\\\ 2580=2400[1+((r)/(100))(1)] \implies \cfrac{2580}{2400}=1+\cfrac{r}{100}\implies \cfrac{43}{40}\implies \cfrac{100+r}{100} \\\\\\ \cfrac{4300}{40}=100+r\implies \cfrac{215}{2}=100+r\implies \cfrac{215}{2}-100=r\implies \boxed{\stackrel{\%}{7.5}=r}`