A music Store buys Instruments and then sells them for 30% more than they paid if the store buys a guitar for $45 what will the
2 answers:
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Answer:
a)0.6192
b)0.7422
c)0.8904
d)at least 151 sample is needed for 95% probability that sample mean falls within 8$ of the population mean.
Step-by-step explanation:
Let z(p) be the z-statistic of the probability that the mean price for a sample is within the margin of error. Then
z(p)= where
- Me is the margin of error from the mean
- s is the standard deviation of the population
- N is the sample size
a.
z(p)= ≈ 0.8764
by looking z-table corresponding p value is 1-0.3808=0.6192
b.
z(p)= ≈ 1.1314
by looking z-table corresponding p value is 1-0.2578=0.7422
c.
z(p)= ≈ 1.6
by looking z-table corresponding p value is 1-0.1096=0.8904
d.
Minimum required sample size for 0.95 probability is
N≥ where
- N is the sample size
- z is the corresponding z-score in 95% probability (1.96)
- s is the standard deviation (50)
- ME is the margin of error (8)
then N≥ ≈150.6
Thus at least 151 sample is needed for 95% probability that sample mean falls within 8$ of the population mean.
Answer:
B) \sqrt{30} - 3 \sqrt{2} + \sqrt{55} - \sqrt{33} \div 2
Step-by-step explanation:
Step 1: First we have to get rid off the roots in the denominator.
To do that, we have to multiply the numerator and the denominator by the conjugate of √5 + √3.
The conjugate of √5 + √3 is √5 - √3.
Now multiply given expression with √5 - √3
(√6 + √11) (√5 - √3)
------------- x -----------
(√5 + √3) (√5 - √3)
Step 2: Multiply the numerators and the denominators.
√6√5 - √6√3 +√11√5 -√11√3
------------------------------------------
(√5)^2 - (√3)^2
Now let's simplify to get the answer.
√30-√18 +√55 - √33
-----------------------------
5 - 3
= √30 -3√2 +√55 [√18 = √9√2 = 3√2]
--------------------------
2
The answer is \sqrt{30} - 3 \sqrt{2} + \sqrt{55} - \sqrt{33} \div 2
Thank you.