Answer:
a) 81.5%
b) 95%
c) 75%
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 266 days
Standard Deviation, σ = 15 days
We are given that the distribution of length of human pregnancies is a bell shaped distribution that is a normal distribution.
Formula:

a) P(between 236 and 281 days)

b) a) P(last between 236 and 296)

c) If the data is not normally distributed.
Then, according to Chebyshev's theorem, at least
data lies within k standard deviation of mean.
For k = 2

Atleast 75% of data lies within two standard deviation for a non normal data.
Thus, atleast 75% of pregnancies last between 236 and 296 days approximately.
Answer:
Therefore the value of 'y' is,

Step-by-step explanation:
Given:

To Find:
y= ?
Solution:
........Given
Step 1. Adding 50 to both the side we get

Step 2. Dividing by 10 on both the side we get

Therefore the value of 'y' is,

Answer:
x= -4
Step-by-step explanation:
=> 1+2x= 4x+9
=> 1-9=4x-2x
=> -8 = 2x
=> x = -8/2
=> x= -4
hope it's helpful to you ☺️
Answer:
The pieces are 55 inches, 55 inches and 46 inches long
Step-by-step explanation:
A 13ft board is to be cut into three pieces consisting of two equal length ones. The third one is 9in shorter than each of the other two.
Let us first convert the length of the board to inches:
1 ft = 12 inches
13 ft = 12 * 13 = 156 inches
Let the length of each of the other two pieces be x.
Therefore, the length of the third piece is (x - 9)
Therefore, the sum of the lengths of the three pieces is equal to 156 inches. This means that:
x + x + (x - 9) = 156
x + x + x - 9 = 156
=> 3x = 156 + 9
3x = 165
x = 165 / 3 = 55 inches
Each of the first two pieces are 55 inches long.
The length of the third piece will be:
55 - 9 = 46 inches
The pieces are 55 inches, 55 inches and 46 inches long.