Need help please and thank you

To complete your spring schedule, you must add calculus and physics. at 9: 30, there are three calculus sections and two physics sections; while at 11: 30, there are two calculus sections and three physics sections. how many ways can you complete your schedule if your only open periods are 9: 30 and 11: 30?

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

Find the domain and range of the following function f(x) = 51x - 21+ 4