Manuel and Rita bought CDs at the music store. Rita's CDs originally cost three times more than Manuel's CDs, but she received a $9 discount. If Rita spent $21 total, which equation can be used to find the amount Manuel spent?

Question

ranga · Answer

Assume Manuel's CD costs x dollars.
You can derive Rita's cost from that.

anonymous · Answer

I have trouble writing the equation..

calculusxy · Answer

we will use "r" standing for Rita 
also "m" for Manuel 

m(3)-9=the price for Manuel's cd

calculusxy · Answer

Okay what we will do is divide 21 by 3 which equals to seven. 

So Manuel's cd is $7