A representative sample of trees in a forest shows the trees to have a mean circumference of 19.7 inches and a standard deviation of 1.3 inches. Assuming the circumferences are normally distributed, what is the z-score for a tree with a circumference of 22 inches?

Sasha drank 8 bottles of water everyday for a week. how many bottles of water did she drink in total?

Dexter read 11 science fiction books and 5 history books. lena read 9 science fiction books and 4 history books. compare the students’ ratios of science fiction books to history books. 1. determine the ratios’ form:    science fiction books to history books 2. write the ratios as fractions:    dexter: 115; lena: 94 3. rewrite with a common denominator. 4. compare. 5. answer the question. determine which shows the correct comparison of the ratios for this problem.

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827