David's Parents have a sandwich shop. They sell sandwiches for $5 each and bottles of water for $1 each. The owners, David's Parents, need to earn a total of
$100 by the end of the day.
a) Write a linear equation that describes the problem
b) What are the slope and the y-intercept and what do they represent?
c) Graph the linear equation the shop's revenue. Make sure to label both axes with
appropriate titles.
d) Then use the graph to determine how many sandwiches the shop must sell if no
waters are sold.

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.