Find the time required for an investment of 5000 dollars to grow to 7800 dollars at an interest rate of 7.5 percent per year, compounded quarterly. Your answer is \( t=\square \) years.

a. Sarfo borrowe of \( \$ 25.000 \) from AFLAk financial services at \( 21 \% \) simple intrest per annum for 3 years. if he was able to pay back the loan in 2 years af equal yearly instalments, how much did he pay each year?

A continuously compounded savings account had an initial deposit of \( \$ 10000 \) and 10 years later has a balance of \( \$ 13125.87 \). At what interest rate was the savings account?

Luis ganha um salário-base de \( \$ 150,00 \) por semana, com uma comissão adicional de \( 14 \% \) sobre tudo que ele vender. Luis vendeu \( \$ 6.050,00 \) em produtos na semana passada. Quanto foi o salário total de Luis na última semana?

04. Una persona debería pagar su deuda el 2 de mayo no lo hace sino el 18 del mismo mes, lo que aumenta su deuda en S/. 18. Si estaba impuestaa \( 4 \% \) de interés anual. ¿Cuánto debía el esa persona? te \( \begin{array}{ll}\text { a) } 10215 & \text { b) } 10512 \\ \text { c) } 10125 & \text { d) } 10251 \\ \text { e) N.A } & \end{array} \)

3. ( Ingreso marginal ) Si la ecuación de demanda es \( 10 p+x+0.01 x^{2}=700 \), calcule el ingreso margina cuando \( p=10 \)