Answer:
The correct option is;
A. The mean speed and the range of the speeds of the motorists decreased
Step-by-step explanation:
Here we have the speeds given as
Before Sign Installation
Speed Frequency
20 1
24 1
25 4
30 2
35 2
38 1
40 1
∑ 212 12
Mean = 17.67
Median (25 + 30)/2 = 27.5
Range = 40 - 20 = 20
After Sign Installation
22 1
28 1
30 3
∑ 160 12
Mean = 160/12 = 13.33
Median = (25+28)/2 = 26.5
Range = 35 - 20 = 15.
Therefore, the mean speed and the range of the speeds of the motorists decreased
x=-2 y=-6
Step-by-step explanation
5x+4=-3x-12
+3 +3x
8x+4=-12
-4 -4
8x=-16
÷8 ÷8
x=-2
Looking for y too, plug x into the original equation
5(-2)+4
-10+4
-6
y=-6