Let a and b be subsets of a universal set u and suppose n(u)=400, n(a)=135, n(b)=80, and n(a n b)=60. find the number of elements in the set n(ac n bc)

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

If the alternate hypothesis of an experiment is “the true mean height of the giraffes is more than 15 feet” what is the null hypothesis?

Which of these figures must be a rectangle?