The formula S- 2 gives the partial sum of an arithmetic sequence. What is the formula solved for an?

At the newest animated movie, for every 9 children, there are 4 adults. there are a total of 39 children and adults at the movie.

Svetlana's hair is 4 4 centimeters ( cm cm) long. her hair grows 1 . 5 cm 1.5cm per month. svetlana wants her hair to be less than 1 6 cm 16cm long. write an inequality to determine the number of months, m m, svetlana can allow her hair to grow so that it is less than 1 6 cm 16cm long.

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.