Given :
Stephanie took a science exam that had two parts. Part 1: She got 16 questions correct, which was 4/5 of the number of part 1 questions. Part 2: She got 16 questions correct, which was 2/3 of the number of part 2 questions.
To Find :
The total number of questions on Stephanie's exam.
Solution :
Let, number of questions in Part 1 is x :

Let, number of questions in Part 2 is y :

Therefore, total number of questions on Stephanie's exam are 20 + 40 = 60.
Hence, this is the required solution.
<h3> Answer:</h3><h2>surface area is 227•1</h2><h2>volume is 321•7</h2>
Step-by-step explanation:
diameter is 8•5
radius is d/2
8•5/2
=4•25
surface area = 4πr^2
4×22/7×4•25×4•25
=1589•5/7
=227•1
Volume= 4/3πr^3
4/3×22/7×4•25×4•25×4•25
4/3×22/7×76•76
=321•7
Hope it helps
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<h2><u>
Answer with explanation</u>
:</h2>
Let
be the average life of light bulbs.
As per given , we have
Null hypothesis : 
Alternative hypothesis : 
Since
is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Formula for Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For
, we have

Using z-value table , Critical one-tailed test value for 0.06 significance level :

Decision : Since critical z value (1.5548) < test statistic (1.6180), so we reject the null hypothesis .
[We reject the null hypothesis when critical value is less than the test statistic value .]
Conclusion : We have enough evidence at 0.06 significance level to support the claim that the new filament yields a longer bulb life
Answer:
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