The water department checks the city water supply on a regular basis for contaminants such as trihalomethanes (thms). the water department takes 200 samples and estimates that the concentration of thms in your drinking water is 3 ppb (parts per billion), with a standard deviation of 0.3 ppb. assuming the samples were random and unbiased how much confidencr can you have in this data? a. 95% confident the average concentration of pcbs in the water supply is between 2.4 ppb and 3.6 ppb. b. 68% confident the average concentration of pcbs in the water supply is between 2.9 ppb and 3.1 ppb..

Someone answer this asap rn for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =

Mr. and mrs. wallace have decided to buy a car for $21,600. they finance $15,000 of it with a 5-year auto loan at 2.9% arp. what will be their monthly payment be? a. $268.20 b. $268.86 c. $269.54 d. $387.16 i need !

Asquare has a side that measures 11 units. what is the area of a circle with a circumference that equals the perimeter of the square? use 3.14 for π, and round your answer to the nearest hundredth. 1519.76 units2 379.94 units2 616.56 units2 154.14 units2