Jacob has a piece of toast that has butter on one side, and he dropped it twice. both times it landed with the butter side up. if he drops it two more times, what is the probability that it will have landed butter side up a total of three times? one over four one over two one over three two over three

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?

The management of a supermarket wants to adopt a new promotional policy of giving a free gift to every customer who spends more than a certain amount per visit at this supermarket. the expectation of the management is that after this promotional policy is advertised, the expenditures for all customers at this supermarket will be normally distributed with a mean of $95 and a standard deviation of $20. if the management wants to give free gifts to at most 10% of the customers, what should the amount be above which a customer would receive a free gift?