On average, a person’s heart beats about 4.2
×
1
0
7
4.2×10
7
times per year. There are about
7
,
600
,
000
,
000
7,600,000,000 people in the world. Use this data to approximate the number of heartbeats for all the people in the world per year. Expressing your answer in scientific notation in the form
a
×
1
0
b
a×10
b
, what are the values of
a
a and
b
b?

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.

1jessica's home town is a mid-sized city experiencing a decline in population. the following graph models the estimated population if the decline continues at the same rate. select the most appropriate unit for the measure of time that the graph represents. a. years b. hours c. days d. weeks

John has 1/2 pound of oranges to share with julie. if they share the oranges equally, how much will each of them have?