I need help with my College Algebra (ads on radio station)

A disk jockey must play 16 commercial spots during 1 hour of a radio station. Each commercial is either 30 seconds or 60 seconds long. If the total commercial time during 1 hour is 13 minutes, how many 30-second commercials were played that hour? How many 60-second commercials?

How many 30-second commercials were played that hour?

How many 60-second commercials were played that hour?

Re: I need help with my College Algebra

let x = number of 30 second spots
y = number of 60 second spots

x + y = 16

30x + 60y = 13(60)

solve the system for x and y