HELPP PLZ (12 points btw)

Which of the following is most likely the next step in the series?

(a) (8%) compute the probability of an even integer among the 100 integers 1! , 2! , 3! , until 100! (here n! is n factorial or n*(n-1)*(n-2) *… 1) (b) (16%) compute the probability of an even integer among the 100 integers: 1, 1+2, 1+2+3, 1+2+3+4, …., 1+2+3+… + 99, and 1+2+3+… + 100

Which expression gives the exact value of x?

The roof of a farm silo is the shape of a hemisphere and is made of sheet tin. if the diameter of the silo is 126.5 feet, how much sheet tin is needed to make the roof? (use π = 3.1416.)