Negative two fifths plus one half

Which one is the correct answer, and why?

Maddie's rectangular kitchen has an area of 10 square yards and a length of 3 3/4 yards.how many yards wide is maddie's kitchen?

Use the given degree of confidence and sample data to construct a confidence interval for the population mean mu . assume that the population has a normal distribution. a laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 185 milligrams with sequals 17.6 milligrams. a confidence interval of 173.8 mgless than muless than 196.2 mg is constructed for the true mean cholesterol content of all such eggs. it was assumed that the population has a normal distribution. what confidence level does this interval represent?