Answer:
Around 2397 Americans must be surveyed to get a margin of error of 2%.
Step-by-step explanation:
We are given the following in the question:
Proportion of US residents who thinks marijuana should be made legal = 48%

We have to construct a 95% confidence interval.
Margin of error = 2% = 0.02
Formula for margin of error =


Putting values, we get,

Thus, around 2397 Americans must be surveyed to get a margin of error of 2%.
2.7 is 27/10 and 3.6 is 18/5
I assume the denominator is

.
C = 120 B = 75
120+75 = 195