An accident in a laboratory results in a room being contaminated by a radioisotope with a half-life of 8 days. If the radiation is measured to be eight times the maximum permissible level, how much time must elapse before the room is safe to enter?

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

Write a fraction less than 1, which has a denominator of 6 and is greater than 3/4 plz answer !

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?