<span>So we need to find the average speed of the bus that travels 20 km in 30 minutes. Average speed is defined as: Average speed=distance travelled/time taken or: v=s/t. We know s=20 km and t=30 minutes=0.5h. So after we input our numbers in the equation, we get: v=20km/0.5h=40km/h. So the correct answer is C) 40km/h.</span>
I'm in seventh grade. I haven't learned that yet.
try asking your teacher.
By using two arbitrary points on the line, we can find the slope using the slope formula:

We'll use the points (0, 4) and (5, 1) for this.
1 - 4 / 5 - 0
-3 / 5
The slope of the line is -3/5.
So basically... you divide the 3 to 2 and that's how you get the decimal. The decimal is... 0.666666666667