Jared has a wooden board that is 11 ft long. He wants to cut it into two pieces so that the longer piece is 4 ft less than 4 tim
1 answer:
Answer
Find out the length of the shorter and longer pieces of a board .
To prove
Let us assume that the length of the shorter pieces be x.
As given
Jared has a wooden board that is 11 ft long.
He wants to cut it into two pieces so that the longer piece is 4 ft less than 4 times the length of the shorter piece.
Than the length of the longer pieces = 4x - 4
Than the equation becomes
x + 4x - 4 = 11
5x = 11 + 4
5x = 15
x = 3 ft
Therefore the length of the shorter pieces be 3 ft .
The length of the longer pieces = 4x - 4
= 4 × 3 - 4
= 12 - 4
= 8 ft
Therefore the length of the longer pieces be 8 ft .
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Answer:
x= -2 and 9
Step-by-step explanation:
factorize it
- 18 = 2×3×3
TO MAKE IT 7
3×3=9
9-2 =7
x(x+9)-2(x+9)=0
x-2=0 ,x+9=0
x =2 x=-9
Answer:
a) Mean blood pressure for people in China.
b) 38.21% probability that a person in China has blood pressure of 135 mmHg or more.
c) 71.30% probability that a person in China has blood pressure of 141 mmHg or less.
d) 8.51% probability that a person in China has blood pressure between 120 and 125 mmHg.
e) Since Z when X = 135 is less than two standard deviations from the mean, it is not unusual for a person in China to have a blood pressure of 135 mmHg
f) 157.44mmHg
Step-by-step explanation:
When the distribution is normal, we use 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.
If X is two standard deviations from the mean or more, it is considered unusual.
In this question:
a.) State the random variable.
Mean blood pressure for people in China.
b.) Find the probability that a person in China has blood pressure of 135 mmHg or more.
This is 1 subtracted by the pvalue of Z when X = 135.
has a pvalue of 0.6179
1 - 0.6179 = 0.3821
38.21% probability that a person in China has blood pressure of 135 mmHg or more.
c.) Find the probability that a person in China has blood pressure of 141 mmHg or less.
This is the pvalue of Z when X = 141.
has a pvalue of 0.7140
71.30% probability that a person in China has blood pressure of 141 mmHg or less.
d.)Find the probability that a person in China has blood pressure between 120 and 125 mmHg.
This is the pvalue of Z when X = 125 subtracted by the pvalue of Z when X = 120. So
X = 125
has a pvalue of 0.4483
X = 120
has a pvalue of 0.3632
0.4483 - 0.3632 = 0.0851
8.51% probability that a person in China has blood pressure between 120 and 125 mmHg.
e.) Is it unusual for a person in China to have a blood pressure of 135 mmHg? Why or why not?
From b), when X = 135, Z = 0.3
Since Z when X = 135 is less than two standard deviations from the mean, it is not unusual for a person in China to have a blood pressure of 135 mmHg.
f.) What blood pressure do 90% of all people in China have less than?
This is the 90th percentile, which is X when Z has a pvalue of 0.28. So X when Z = 1.28. Then
X = 120
So
157.44mmHg