Question

Luther earned some money doing odd jobs last summer and put it in a savings account that earns 3% interest compounded quarterly after 2 years there is 800.00 in the account how much did Luther earn doing odd jobs

Answer 1

The function we have to use in this case is

$m(t)=m_o\cdot(1+\frac{0.03}{4})^{4t}$

where mo is the initial amount of money. After 2 teats we get that

$\begin{gathered} m_0\cdot(1+\frac{0.03}{4})^8=800 \\ m_0\cdot1.06=800 \\ m_0=\frac{800}{1.06}\approx754.71 \end{gathered}$

SO he earned 755 approximately