Please solve all i will mark brainliest and 15 points.
1 answer:
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Answer:
The correct answer is "(18, 30) minutes".
Step-by-step explanation:
Mean,
= 24
Standard deviation,
= 2
The range of minutes where 99.7% of individuals completed the quiz will be:
=
On substituting the values, we get
=
=
now,
=
=
Or,
=
=
i.e., 18 to 30 minutes
the equations y = –3x + 4 and 3y = –9x + 12 have infinitely many solutions. option B is correct.
<h3>What is the linear system?</h3>It is a system of an equation in which the highest power of the variable is always 1. A one-dimension figure that has no width. It is a combination of infinite points side by side.
Condition for the parallel lines.
L1, ax + bx + c = 0
L2, dx + ey + f = 0
If then lines have infinitely many solutions.
y = –3x + 4 and 3y = –9x + 12
On comparing we have
a = -3 , b = 1, and c = 4
d = -9 , e = 3, and f = 12
Then their ratio will be
Hence y = –3x + 4 and 3y = –9x + 12 have infinitely many solutions.
Thus the option B is correct.
More about the linear system link is given below.
Answer:
Step-by-step explanation:
Sample proportion p is the proportion of favourable numbers to total number in the sample
By central limit theorem and also approximation of binomial to normal , we have sample proportion for large number of samples will be normal
with mean = sample proportion
and std deviation =
Thus we find standard deviation of proportion sample is inversely proportional to the square of the sample size n.
It follows automatically that as sample size increases std deviation decreases.
Here from 80 sample size was made to 200
So std deviation would decrease automatically