Assume that among households with an annual income over $100,000 , 75% own SUVs, while among households with an annual income un
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The general form of a quadratic (second degree) equation is
, where
is called the Discriminant.
The Discriminant determines how many roots the equation will have as follows:
i) if D>0, the equation has 2 roots.
ii) if D=0, the equation has 1 double root.
iii) if D<0, the equation has no roots.
In our equation,
, a=1, b=-5, c=7
so the discriminant is D=(-5)^2-4*1*7=25-28<0
Thus the equation has no roots.
Remark: the equation has no roots in the Real numbers, but it has 2 roots in a larger set of numbers to be discussed in the future, the Complex numbers.
The Discriminant determines how many roots the equation will have as follows:
i) if D>0, the equation has 2 roots.
ii) if D=0, the equation has 1 double root.
iii) if D<0, the equation has no roots.
In our equation,
so the discriminant is D=(-5)^2-4*1*7=25-28<0
Thus the equation has no roots.
Remark: the equation has no roots in the Real numbers, but it has 2 roots in a larger set of numbers to be discussed in the future, the Complex numbers.
Answer: The percent of red lights last between 2.5 and 3.5 minutes = 95.44% approx.
Step-by-step explanation:
Given: Mean time = 3 minutes
standard deviation = 0.25 minutes
The probability of red lights last between 2.5 and 3.5 minutes :-
The percent of red lights last between 2.5 and 3.5 minutes = 95.44% approx.