B. they are directly proportional because she keeps taking 3 at a time to his 1 at a time.
There are 8 sets of 21 cups in 168 cups so 9 times 8 is 72
Answer:
15
Step-by-step explanation:
First do, 30% + 45% = 75%. Then do, 100-75=25.
Lastly,
proportions:
x/60 = 25/100
So your answer is, 15.
The confidence interval for the mean usage of water is (18.7,20.5).
Given population standard deviation of 2.4, mean of 19.5 gallons per day and confidence interval of 98%.
We have to find the confidence interval for the mean usage of water.
To find out the confidence interval we have to first find margin of error.
μ=19.5
σ=2.4
α=0.98
α/2=0.49
We have to find the z value for the p value 0.49 which is z=2.33
Margin of error=z*μ/
=2.33*19.5/
=0.82
lower level=mean -m
=19.5-0.82
=18.68
after rounding upto 1 decimal
=18.7
upper mean = mean+m
=19.5+0.82
=20.52
Hence the confidence interval for the usage of water is (18.7,20.52).
Learn more about margin of error at brainly.com/question/10218601
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I think the answer that u r looking for is C