19. My dad has 9 oak and maple boards from the lumber yard. Each oak board is 1 centimeter thick. Each maple board is 6 centimeters thick. When my dad stacks the boards, the stack is 29 centimeters thick. How many of each type of board does he have?

Aaron invested a total of $4,100, some in an account earning 8% simple interest, and the rest in an account earning 5% simple interest. how much did he invest in each account if after one year he earned $211 in interest? select one: a. $200 at 8%, $3,900 at 5% b. $3,200 at 8%, $900 at 5% c. $900 at 8%, $3,200 at 5% d. $3,900 at 8%, $200 at 5%