The high school band and chorus are putting on a spring concert. the two groups together want to perform no more than 15 songs and the concert has to be 60 minutes or less in length. each piece the band performs is about 5 minutes in length. each piece the chorus sings is about 3 minutes in length. which system of inequalities best represents the number of songs the band performs (x) and the number of longs the chorus performs (y) for the concert?

a) x+y≤15and5x+3y≤60

b) x+y≥15and5x+3y> 60

c) x+y≤60and5x+3y< 15

d) x+y≤15and5x+3y≥60