HELPP please an arithmetic sequence is given below. 30,24,18, 12. Write an explicit formula for the n^th term an’.

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4

Plzzz answer both questions and i will give you 100 points

Margie is practicing for an upcoming tennis tournament. her first serve is good 20 out of 30 times on average. margie wants to know the estimated probability that her first serve will be good at least four of the next six times she serves. how could she design a simulation for this scenario?