How much money invested at 5% compound continuously for 3 years will yield $820

Which of the following is correct interpretation of the expression -4+13

Alicia puts $400 in a bank account. each year the account earns 5% simple interest. how much money will be in her bank account in six months?

Examine this system of equations. what integer should the second equation be multiplied by so that when the two equations are added together, the x term is eliminated? 3/4x+1/7y=6 1/8x-3/5y=16