19. What is the probability of tossing a penny and landing on heads two times in a row?
20. The area of one playing card is 24 square centimeters. 52 cars are stacked on top of each other to make a deck. What is the volume of that solid deck?
19). The probability of landing on heads the first time is 1/2. The probability of landing on heads the second time is 1/2. The probability of landing on heads both times is