About 28% of states are considered swing states. How many states is that

7x+8y=-18, 4x-9y=-3 solve the system of equations

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.

3.4a=57.8 what is the the value of a