Answer:
Here's what I got. First of all, did you meant y=mx+b+mx+mxy+mx=b, because that's undefined, or did you meant y=mx+b+mx+mx, which is b=−3mx+y.
This is a mixture problem.
Let the 9 karat gold to be mixed be x. The 18 karat would weight (200 - x). Since the total = 200g.
mass1 * karat1 + mass2*karat = total mass * total carat
Let mass1 be x g. mass 2 would be = (200 -x)
karat 1 = 9 karat 2 = 18
Total mass = 200g.
Total karat = 14.
9*x + 18*(200 -x) = 14*200
9x + 18*200 - 18*x = 14*200
18*200 + 9x - 18x = 14*200
3600 - 9x = 2800
3600 - 2800 = 9x
800 = 9x
9x = 800
x = 800/9
x ≈ 88.89
Therefore 88.89 grams of 9 karat gold must be mixed.
Answer:
Step-by-step explanation:
the tempayure was at six because it was at 92c and went down to -13c then rose 7c so that means it was at 6 by 6 a.m.
Answer:
Critical value: z = 1.28
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
So it is z with a pvalue of 1-0.1 = 0.9, so z = 1.28
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
So
The lower end of the interval is the mean subtracted by M. So 64.26 - 17.773 = $46.487.
The upper end of the interval is M added to the mean. So 64.26 + 17.773 = $82.033.
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
