X=3 use photomath it will help
They need to buy six because they will end up with fifty four.
(they cant buy five because they would end up with forty five and that wouldnt be enough)
Answer:
15 different pairs.
Step-by-step explanation:
I hope this helps. :D
8.35x-1.5=71.98
Add 1.5 to both sides:
8.35x=73.48
Divide both sides by 8.35:
x=8.8
Answer:
(i) The student who weighed the rock 20 times.
Step-by-step explanation:
The margin of error of a confidence interval is:
![M = z*\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%2A%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
In which z is related to the confidence level,
is the standard deviation of the population and n is the size of the sample.
From the equation above, the larger the size of the sample, the lower the margin is, that is, the narrower the interval is.
In this question:
A student weighed the rock 20 times and other the 5. From above, the one who weighed the rock 20 times will have the more precise interval.
So the correct answer is:
(i) The student who weighed the rock 20 times.