Can someone please answer this?

Mustafa contributes 11% of his $67,200 annual salary to his 401k plan. what is his pretax income

Beth took out a $20,000 loan for college she is borrowing money from two banks. bank a charges an interest rate of 8.5% bank b charges and interest rate of 10.5% after one year alice owes $1860 in interest how much money did she borrow from bank a

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.