A radioactive element decays at a rate of 5% annually. There are 40 grams of the present. How much of the substance remains after 30 years (to the nearest tenth)?

The weight of full–grown tomatoes at a farm is modeled by a normal distribution with a standard deviation of 18.4 grams. the 95 percent confidence interval for the mean weight of the tomatoes is calculated using a sample of 100 tomatoes. what is the margin of error (half the width of the confidence interval)?

What is the ratio for the surface areas of the cones shown below, given that they are similar and that the ratio of their radil and altitudes is 4: 3? 23

Find the solution of this system of equation -7x+y=-20 9x-3y=36