Rebecca had 9/10 of a yard of ribbon. then she gave 7/20 of a yard to a friend. how much does she have left? explain your work

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Astandard american eskimo dog has a mean weight of 30 pounds with a standard deviation of 2 pounds. assuming the weights of standard eskimo dogs are normally distributed, what range of weights would 99.7% of the dogs have? approximately 26–34 pounds approximately 24–36 pounds approximately 28–32 pounds approximately 29–31 pounds

Consider the enlargement of the pentagon. what is the value of x, rounded to the nearest tenth? 2.1 centimeters 3.3 centimeters 7.0 centimeters 15.0 centimeters