Answer:
Option A is correct.
Solution for the given equation is,
Step-by-step explanation:
Given that :
Let
then our equation become;
.....[1]
A quadratic equation is of the form:
.....[2] where a, b and c are coefficient and the solution is given by;
Comparing equation [1] and [2] we get;
a = 2 b = -1 and c =-1
then;
Simplify:
or
or
and
Simplify:
y = 1 and
Substitute y = cos x we have;
⇒
and
⇒
The solution set:
Therefore, the solution for the given equation is,
Answer:
5.48% of the people in line waited for more than 28 minutes
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Mean waiting time of 20 minutes with a standard deviation of 5 minutes.
This means that
What percentage of the people in line waited for more than 28 minutes?
The proportion is 1 subtracted by the p-value of Z when X = 28. So
has a p-value of 0.9452.
1 - 0.9452 = 0.0548.
As a percentage:
0.0548*100% = 5.48%
5.48% of the people in line waited for more than 28 minutes