MATH SOLVE

4 months ago

Q:
# a used bookstore also started selling used CDs and videos. In the first week the store sold a combination of 40 CDs and videos. They charged $4 CD and $6 per video and the total sales were $180. Determine the total number of CDs and videos sold

Accepted Solution

A:

First we must make a system of equations:

c+v=40

4c+6v=180

We can solve this system of equations using substitution

c+v=40

-v -v

_________

c=40-v

4(40-v)+6v=180

160-4x+6v=180

-160 -160

________________

2v=20

v=10

c+v=40

c+10=40

-10 -10

________

c=30

So, there are 30 CDs and 10 videos.

c+v=40

4c+6v=180

We can solve this system of equations using substitution

c+v=40

-v -v

_________

c=40-v

4(40-v)+6v=180

160-4x+6v=180

-160 -160

________________

2v=20

v=10

c+v=40

c+10=40

-10 -10

________

c=30

So, there are 30 CDs and 10 videos.