David rode his bike a total of 214 miles from his house to the store. First he rode 34 mile from his house to his school. Then he rode 14 mile from his school to the library. Finally he rode from the library to the store. How many miles did David ride between the library and the store?

Jeffery conducted a survey in his school and found that 30 of the 50 eighth grade students' favorite subject is mathematics. based on the results, jeffery concluded that out of the 200 students in his school, 120 students' favorite subject is mathematics. select the statement that is true about jeffery's conclusion. a. jeffery's conclusion is not valid because the sample was biased since only 200 students were surveyed. b. jeffery's conclusion is valid because the sample was random since all of the students were eighth grade students. c. jeffery's conclusion is valid because the sample was random. d. jeffery's conclusion is not valid because the sample was biased since all of the students were eighth grade students.

The diameter of a circular chip is doubled to use in a new board game. the area of the new chip will be

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?