30÷5=6
4×5=20
for every 30 green lights there are 20 white lights
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To compare the two classes, the Coefficient of Variation (COV) can be used. The formula for COV is this:
C = s / x
where s is the standard deviation and x is the mean
For the first class:
C1 = 10.2 / 75.5
C1 = 0.1351 (13.51%)
For the second class:
C2 = 22.5 / 75.5
C2 = 0.2980 (29.80%)
The COV is a test of homogeneity. Looking at the values, the first class has more students having a grade closer to the average than the second class.
Answer:
x is the reciprocal of the difference of a and b.
Step-by-step explanation:
ax=bx+1
Subtract by bx on both sides
ax-bx=1
x(a-b)=1
x= 1/(a-b)
(n+20)*2 = 99.2
distribute
2n + 40 = 99.2
subtract 40 from each side
2n = 59.2
divide each side by 2
n = 29.6
