When sending a letter, Bobby pays a fixed amount for letters weighing up to an ounce. He then pays a smaller, fixed amount for e
ach additional ounce (or part of an ounce). The cost of sending the letter in cents is modeled by the function y = 30 + 20(x - 1), where x is the weight of the letter in ounces. What does the number 20 describe?
Supposing that the number are 1-6 there are 3 even numbers, so the probability to roll an even number is 3/6=1/2. Probability of flipping head is 1/2 so combined probability=1/2×1/2=1/4.