PLZ HELP WILL GIVE BRAIN THING AND EXTRA POINTS !What is the least common denominator of the rational expressions below? ​

Astandard deck of cards contains 52 cards. one card is selected from the deck. (a) compute the probability of randomly selecting a seven or king. (b) compute the probability of randomly selecting a seven or king or jack. (c) compute the probability of randomly selecting a queen or spade.

Astuntman jumping off a 20-m-high building is modeled by the equation h=20-5t^2, where t is the same in seconds. a high-speed camera is ready to film him between 15m and 10m above the ground. for which interval of time should the camera film him?

(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.)