Answer:
work is shown and pictured
Answer:
The standard deviation is 7.7
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

8 percent of the scores are above 89
This means that X = 89 has a pvalue of 1 - 0.08 = 0.92. So when Z = 89, Z = 1.405.





The standard deviation is 7.7
Answer:
125x - 33x⁴
Pull out like factors :
125x - 27x⁴ = -x • (27x3 - 125)
Factoring: 27x³- 125
Theory : A difference of two perfect cubes, a³ - b³ can be factored into
(a-b) • (a² +ab +b²)
(a-b)•(a²+ab+b²) =
a³+a²b+ab²-ba²-b²a-b³ =
a³+(a2b-ba²)+(ab²-b²a)-b³ =
a³+0+0+b³ =
a³+b³
Check : 27 is the cube of 3
Check : 125 is the cube of 5
Check : x³ is the cube of x¹
Factorization is :
(3x - 5) • (9x² + 15x + 25)

The total revenue that is obtained from selling the tickets is the sum of the revenue from selling the child tickets and the adult tickets. If x and y are the number of child and adult ticket, the equation that would represent the given is,
4x + 6y = 420
The equation that would allow us to solve for the number of adult tickets is,
6y = 420 - 4x
Simplifying,
<em>y = 70 - 2x/3</em>