Answer: it's the first option.
Step-by-step explanation: i just graphed it out, and it showed as the y-intercept was -1.5, and the x-intercept was -1.
Answer:
The 90% confidence interval for the population mean iron concentration is between 0.167 cc/m³ and 0.195 cc/m³.
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
, so 
Now, find M as such

In which
is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 0.181 - 0.0140 = 0.167 cc/m³.
The upper end of the interval is the sample mean added to M. So it is 0.181 + 0.0140 = 0.195 cc/m³.
The 90% confidence interval for the population mean iron concentration is between 0.167 cc/m³ and 0.195 cc/m³.
10.5 hours
let t be time then distance travelled by both is
Mr Burges ⇔ d = 50t ( distance = speed × time )
Mrs Burges ⇒ d = 70(t - 3)
At the point of overtaking both will have travelled the same distance
equating their distance and solving for t
70(t - 3) = 50t
70t - 210 = 50t ( subtract 50t from both sides )
20t - 210 = 0 ( add 210 to both sides )
20t = 210 ( divide both sides by 20 )
t = 10.5 hours
Im guessing he answered 30 correct, let me know if im correct
Probably is 64% I just think it’s is but I’m not sure