Question

a store sold 8/5 as many dvd's as cd's. the total number of dvd's and cds sold tha day was 273. how many dvd's were sold

Answer 1

If we call the number of DVDs x and the number of CDs y we can form two equations.
x=8/5*y and x+y=273
5x=8y and x=273-y
Now if we sub 273-y for x in the first equation:
5(273-y)=8y
1365=13y
y=105
x=273-105
x=168
168 DVDs were sold