If a runner maintains a constant speed of 12 miles an hour how long will it take to complete a half marathon race of 13.1 miles???

At 12 mph, how long does it take to go 13.1 miles?

We know that distance = rate * time
So we know that 13.1 = 12 * time
We can now see that time = 13.1/12 = 1.092 (hours)
That's approximately 1 hour and .092*60=5.52 minutes.

Variables,control,conclusion and finally scientific theory

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom