What is the answer to 42 + 8 = 20

Will give a: 122 b: 90 c: 48 d: 180

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

Now, martin can reasonably guess that the standard deviation for the entire population of people at the mall during the time of the survey is $1.50. what is the 95% confidence interval about the sample mean? interpret what this means in the context of the situation where 95 people were surveyed and the sample mean is $8. use the information in this resource to construct the confidence interval.