Because the probability is uniform (equally likely) between 20 and 100 pounds, the probability distribution is uniform between 80 and 100 pounds, with the value 1/(100-20) = 1/80 chocolates/pound.
Let x = random variable that represents pounds of chocolate consumed.
Therefore
P(x < 60) = (60 - 20)*(1/80) = 1/2.
Answer: The probability is 1/2.
