Answer:
Step-by-step explanation:
A suitable table or calculator is needed.
One standard deviation from the mean includes 68.27% of the total, so the number of bottles in the range 20 ± 0.16 ounces will be ...
0.6827·26,000 = 17,750 . . . . . within 20 ± 0.16
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The number below 1.5 standard deviations below the mean is about 6.68%, so for the given sample size is expected to be ...
0.66799·26,000 = 1737 . . . . . below 19.76
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<em>Comment on the first number</em>
The "empirical rule" tells you that 68% of the population is within 1 standard deviation (0.16 ounces) of the mean. When the number involved is expected to be expressed to 5 significant digits, your probability value needs better accuracy than that. To 6 digits, the value is 0.682689, which gives the same "rounded to the nearest integer" value as the one shown above.
I:2x – y + z = 7
II:x + 2y – 5z = -1
III:x – y = 6
you can first use III and substitute x or y to eliminate it in I and II (in this case x):
III: x=6+y
-> substitute x in I and II:
I': 2*(6+y)-y+z=7
12+2y-y+z=7
y+z=-5
II':(6+y)+2y-5z=-1
3y+6-5z=-1
3y-5z=-7
then you can subtract II' from 3*I' to eliminate y:
3*I'=3y+3z=-15
3*I'-II':
3y+3z-(3y-5z)=-15-(-7)
8z=-8
z=-1
insert z in II' to calculate y:
3y-5z=-7
3y+5=-7
3y=-12
y=-4
insert y into III to calculate x:
x-(-4)=6
x+4=6
x=2
so the solution is
x=2
y=-4
z=-1
You would simplify this expression by adding the coefficients 14 and -5.