Start and End Values

An investment of $\displaystyle \pounds 3500$ grows to $\displaystyle \pounds 3950$ over $\displaystyle 4$ years.
Calculate the annual effective rate of interest.
Give your answer as a percentage to 2 decimal places.

A deposit of $\displaystyle \pounds 8200$ grows to $\displaystyle \pounds 9100$ over $\displaystyle 30$ months.
Calculate the monthly effective rate of interest.
Give your answer as a percentage to 3 decimal places.

$\displaystyle \pounds 600$ is borrowed and no repayments are made.
After $\displaystyle 7$ months the amount owed is $\displaystyle \pounds 693$.
Calculate the monthly effective rate of interest.
Give your answer as a percentage to 2 decimal places.

An account pays an effective rate of interest of $\displaystyle 3\%$ per year.
After $\displaystyle 5$ years the balance is $\displaystyle \pounds 9280$.
Calculate the amount originally deposited.
Give your answer to the nearest penny.