Santa's elves are creating treat bags containing a selection of kit kats, reese's cups and almond joys. (a) how many different types of bags can they make containing 15 chocolate bars. (b) how many different types of bags can they make containing 15 chocolate bars if santa wants to have at least 1 kit kat(s), 1 reese's cup(s) and 2 almond joy(s) in the bag.

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Write the sine and cosine values of a, b, respectively, in the figure for (1) and (2) + explanation.

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.