Ur equations are :
C = 0.03t + 20...this is company A
C = 0.07t + 5....this is company B
now...for them to be equal...set them equal and solve for t
0.03t + 20 = .07t + 5
-5 + 20 = 0.07t - 0.03t
15 = 0.04t
15/0.04 = t
375 = t.......there would have to be 375 texts
Answer:
the anser from what i see should be option 1
Step-by-step explanation:
The reason why i say this is because number 1 is linear which means it is just multipying but your multiplying and adding and its not option 3 because question 5 said the questions started at 1
<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
The answer is the second choice. Hope that was helpful