Given the discovery of chlorine-resistant pathogens, ozone is commonly used as an alternate disinfectant for drinking water. Ozone decay in water nearly follows first-order kinetics, such that its concentration decreases by half every 12 minutes (t1/2 = 12 min). A water supplier wants to inject ozone into a 4.0-ft diameter pipe that is 3,000 ft long receiving a steady water flow of 15,000 gal/min. What concentration of ozone (in mg/L) should be injected at the head of the pipe so that there will be an ozone concentration of 1.0 mg/L at the pipe’s exit? The pipe may be modeled as an ideal plug flow reactor.

The wheels of a bicycle have a diameter of 70cm. how many meters will the bicycle travel if each wheel makes 50 revolutions

An automobile assembly line operation has a scheduled mean completion time, μ, of 12 minutes. the standard deviation of completion times is 1.6 minutes. it is claimed that, under new management, the mean completion time has decreased. to test this claim, a random sample of 33 completion times under new management was taken. the sample had a mean of 11.2 minutes. assume that the population is normally distributed. can we support, at the 0.05 level of significance, the claim that the mean completion time has decreased under new management? assume that the standard deviation of completion times has not changed.

Which statement is true about a number and its additive inverse? a. their product is always one. b. their sum is always one. c. they are always reciprocals of each other. d. their sum is always zero.