Alice and Dave left school at the same time walking in opposite directions. Alice walked at an average speed of 280 ft/min and Dave walked at an average speed of 320 ft/min.

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.

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?

Arational number that is equivalent to -20/4?