Answer:
Step-by-step explanation:
Since the length of time taken on the SAT for a group of students is normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - u)/s
Where
x = length of time
u = mean time
s = standard deviation
From the information given,
u = 2.5 hours
s = 0.25 hours
We want to find the probability that the sample mean is between two hours and three hours.. It is expressed as
P(2 lesser than or equal to x lesser than or equal to 3)
For x = 2,
z = (2 - 2.5)/0.25 = - 2
Looking at the normal distribution table, the probability corresponding to the z score is 0.02275
For x = 3,
z = (3 - 2.5)/0.25 = 2
Looking at the normal distribution table, the probability corresponding to the z score is 0.97725
P(2 lesser than or equal to x lesser than or equal to 3)
= 0.97725 - 0.02275 = 0.9545
(10+2x)(8+2x) = 120
4x^2 + 36x + 80 = 120
x^2 + 9x + 20 = 30
x^2 + 9x - 10 = 0
(x+10)(x-1) = 0
x = 1 inch dimension
<h3>The expression for the length of fabric used for each doll is
</h3>
<em><u>Solution:</u></em>
Given that,
Margaret has 16 yards of fabric
she is making dresses for z doll
Therefore,
Total length of fabric = 16 yards
Number of dresses = z dolls
Therefore,
Thus, the expression for the length of fabric used for each doll is
X = k x y
21 = k x 3
k = 7
x = 7y
x = 7(10)
x = 70
