A chemical company makes two brands of antifreeze. The first brand is 70% pure antifreeze, and the second brand is 80% pure antifreeze. In order to obtain 120 gallons of a mixture that contains 80% pure antifreeze, how many gallons of each brand of antifreeze must be used?

(b) suppose that consolidated power decides to use a level of significance of α = .05, and suppose a random sample of 100 temperature readings is obtained. if the sample mean of the 100 temperature readings is x⎯⎯ = 60.990, test h0 versus ha and determine whether the power plant should be shut down and the cooling system repaired. perform the hypothesis test by using a critical value and a p-value. assume σ = 5. (round your z to 2 decimal places and p-value to 4 decimal places.)