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?

Astandard deck of cards contains 52 cards. one card is selected from the deck. (a) compute the probability of randomly selecting a seven or king. (b) compute the probability of randomly selecting a seven or king or jack. (c) compute the probability of randomly selecting a queen or spade.

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed