Eric purchased three music CDs and a sweatshirt from a band's online store and received a 20% discount. He paid $100 for his purchase. The following week, the same store offered a 40% discount on all its products. Eric's friend Neil took advantage of the sale and bought four music CDs and two sweatshirts for $120

Assuming that the actual prices of the music CDs and the sweatshirts are unchanged, the price of a music CD is $
a. 20
b. 25
c. 30
d. 50
and the price of a sweatshirt is $
a. 20
b. 25
c. 30
d. 50

Question

Eric purchased three music CDs and a sweatshirt from a band's online store and received a 20% discount. He paid $100 for his purchase. The following week, the same store offered a 40% discount on all its products. Eric's friend Neil took advantage of the sale and bought four music CDs and two sweatshirts for $120

Assuming that the actual prices of the music CDs and the sweatshirts are unchanged, the price of a music CD is $ 
a. 20
b. 25
c. 30
d. 50
and the price of a sweatshirt is $
a. 20
b. 25
c. 30
d. 50

anonymous · Answer

ahhh some one has the same ??? as mine

anonymous · Answer

Let c = CD
Let s= sweatshirt

3c+s=100/.8
4c+2s=120/.6

3c+s=125
4c+2s=200

Multiply the first equation by -2
-2(3c)+(-2)(s)=-2(125)
-6c-2s=-250

Eliminate the s variable by adding -6c-2s=-250 to the second equation 4c+2s=200

We get the following:
-2c=-50
c=25

So the regular price of the cd is $25

Plug the $25 for each cd into the first equation and solve for s.

3(25) + s = 125
s=50

So cost of a sweatshirt is $50