1. The cost that a carpet cleaning company charges is directly proportional to the number of rooms cleaned. The cost is $25 for each room. (a) Write an equation to represent the cost. Show your work!
(b) How many rooms can a hotel pay the company to clean for $200? Write and solve an equation. Show your work!
(c) Suppose the hotel plans to tip the carpet cleaners $25. In that case, how many rooms can the hotel get cleaned for $200? Write and solve an equation. Show your work!

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?

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.

Is there an x intercept in the equation 60*1.15^x