Answer:
440 Rock CDs
Step-by-step explanation:
Let number of rock CDs be "r", and
number of Jazz CDs be "j"
4 times as many Rock as Jazz, so we can write:
r = 4j
Total of 550 CDs, thus we can write equation 2:
r + j = 550
Now we replace 2nd equation with 1st equation and find j first:
r + j = 550
4j + j = 550
5j = 550
j = 550/5
j = 110
Now, finding r:
r = 4j
r = 4(110)
r = 440
There are 110 Jazz CDs and 440 Rock CDs
