A company earns £3,178,784 in 2016. 4/7 of the income is spent on salaries. How much money does the company spend on salaries in 2016?

Can somebody me out with this question

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

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.