Simplify this, include instructions

12. the amount of money in a bank account decreased by 21.5% over the last year. if the amount of money at the beginning of the year is represented by ‘n', write 3 equivalent expressions to represent the amount of money in the bank account after the decrease?

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

Maria walks a round trip of 0.75 mile to school every day. how many miles will she walk in 4.5 days