Can someone please help me understand ? Mathematics Assignment Help

The world record time for a certain swimming event was 63.2 seconds in 1950. Each year thereafter, the world record time decreased by 0.4 second.

(a) Use a formula to express the world record time as a function of the time since 1950. (Let t be the time in years since 1950 and R the record time in seconds.)
R = 

 

(b) Express using functional notation the world record time in the year 1975.

Calculate the world record time in the year 1975.
 sec 

In a retail store the stock turnover rate of an item is the number of times that the average inventory of the item needs to be replaced as a result of sales in a given time period. It is an important measure of sales demand and merchandising efficiency. Suppose a retail clothing store maintains an average inventory of 50 shirts of a particular brand.

(a) Suppose that the clothing store sells 250 shirts of that brand each year. How many orders of 50 shirts will be needed to replace the items sold?
 orders

(b) What is the annual stock turnover rate for that brand of shirt if the store sells 250 shirts each year?
 times/yr

(c) What would be the annual stock turnover rate if 550 shirts were sold?

 times/yr

ou own a motel with 30 rooms and have a pricing structure that encourages rentals of rooms in groups. One room rents for $80.00, two for $78.00 each, and in general the group rate per room is found by taking $2 off the base of $80 for each extra room rented.

(a) How much money do you charge per room if a group rents 3 rooms?
$  

What is the total amount of money you take in?
$  

(b) Use a formula to give the rate you charge for each room if you rent n rooms to an organization.

(c) Find a formula for a function R = R(n) that gives the total revenue from renting n rooms to a convention host.
R(n) = 

A rental car agency charges $26.00 per day and 25 cents per mile.