The pesticide DDT is banned in most countries because of its long-lasting toxic effects on
humans and animals. The half-life of DDT is
approximately 15 years. A sample area of soil
contains 100 g of DDT. Determine the amount
of DDT in the soil after 70 years.

Need to finish my juan wants to build a greenhouse in his back yard. he needs to maximize the ratio of floor area to structure volume in order to provide the most room for plants while minimizing the area to be heated. find the description of the structure that best meets juan’s criteria. a.) a hemisphere with a diameter of 12 feet b.) a cube with a side length of 12 feet c.) a cone with a diameter of 12 feet and a height of 10 feet d.) a square pyramid with a base side length of 12 feet and a height of 9 feet