David is twice as old as rick. the sum of ricks age and davids age is 81. how old is rick?

Convert 50 kilogram to pounds. (the conversion factor from kilogram to pound is 2.2046.) a. 52.2 lb. b. 110.2 lb. c. 22.6 lb. d. 47.8 lb.

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.

How can you tell when x and y are not directly proportional?