Grandma is trying out a new recipe for raisin bread. Each batch of bread dough makes five loaves, and each loaf contains 10 slices of bread.
(a) If she puts 250 raisins into a batch of dough, what is the probability that a randomly chosen slice of bread contains less than 5 raisins?
(b) How many raisins must she put in so that the probability that a randomly chosen slice of bread will have no raisins is 0.01?