X+y = 12
x-y = 3
x = 3+y
Substitute it in 1st equation,
3+y+y=12
2y = 9
y = 4.5
Substitute it in 1st eq.,
x = 12-4.5 = 7.5
So, the two numbers are 7.5 & 4.5
Hope this helps!
Step-by-step explanation:
the volume of a cube is
side³.
since the volume is 27 m³, the individual side lengths are then the cubic root of 27 = 3 m.
the surface area is 6 squares of 3×3 = 9m², so in total
9 × 6 = 54 m²
Using the z-distribution, the p-value would be given as follows:
b) 0.0086.
<h3>What are the hypothesis tested?</h3>
At the null hypothesis we test if the means are equal, hence:
At the alternative hypothesis, it is tested if they are different, hence:
<h3>What are the mean and the standard error for the distribution of differences?</h3>
For each sample, they are given as follows:
Hence, for the distribution of differences, they are given by:
.
<h3>What is the test statistic?</h3>
The test statistic is given by:
In which 
is the value tested at the null hypothesis.
Hence:
z = -2.63.
Using a z-distribution calculator, for a two-tailed test, with z = -2.63, the p-value is of 0.0086.
Hence option B is correct.
More can be learned about the z-distribution at brainly.com/question/13873630
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Answer:
260 gallons
Step-by-step explanation:
An estimate of 26.5% of the water used each day is for cleaning and a family uses 68.9 gallons of water a day for cleaning,
Percentage of water used for cleaning= 26.5%
Gallons of water used for cleaning= 68.9
Let the number of gallons used everyday be represented by g. This will give:
26.5% of g = 68.9
26.5/100 × g = 68.9
0.265 × g = 68.9
0.265g = 68.9
Divide both side by 0.265
0.265g/0.265 = 68.9/0.265
g= 260
260 gallons of water are used everyday
