I need 10.5 trees to make 5 cabins. How many trees do I need to make 3 cabins. Then how many trees to make 7 cabins

With number 11 ( show how you got the answer)

(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.)

Could someone me with this question i’ve been stuck on it for 20 minutes