Answer:
They can either decrease the confidence level or increase the sample size, that is, survey more students.
Step-by-step explanation:
The width of a confidence interval is given by:

In which z is the critical value correponding to the confidence level(higher confidence level, higher z is),
is the standard deviation of the population and n is the size of the sample.
The students realize that this interval contains a large margin of error. What can they do to make a narrower interval?
Looking at the formula for M, they can either decrease the confidence level or increase the sample size, that is, survey more students.
Answer:
the answer would be 8x-10
You do 4/1 divided by 2/9
4 2
_ divided by _
1 9
Equals 18
(You have to multiply by the reciprocal)
4/1 times 1/4
And
2/9 times 1/4
Hope I helped!!!