What's mass?

o a. the sum of the number of protons and
neutrons in an atom
b. a measure of the amount of matter an
object contains
c. a measure of an element's attraction
for electrons
o d. the force that gravity exerts upon an
object

The physical fitness of an athlete is often measured by how much oxygen the athlete takes in (which is recorded in milliliters per kilogram, ml/kg). the mean maximum oxygen uptake for elite athletes has been found to be 60 with a standard deviation of 7.2. assume that the distribution is approximately normal.

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Which number completes the inequality? 2/3 < _ < 7/9