What’s is slope and how do you find rise over run

A slope is a surface of which one end or side is at a higher level than another both a rising or falling surface.

And to find the rise over run use the slope to find a second point on the line. You will start with the y-intercept and rise up or down and then run left or right depending on the sign of the slope.

The probability is that they will all be girls is 1/21 and it is dependent since you can not pick the same one all three times.