Wyatt has a $30 online gift card. he plans to buy as many books as he can. the cost of each book is $4. there is also a single shipping charge of $2. how many books can he buy without spending more than his gift card amount?

In a survey of 1015 adults, a polling agency asked, "when you retire, do you think you will have enough money to live comfortably or not. of the 1015 surveyed, 534 stated that they were worried about having enough money to live comfortably in retirement. construct a 90% confidence interval for the proportion of adults who are worried about having enough money to live comfortably in retirement.