Respuesta :

Let c = the price of a cd
Let t = the price of cassette tapes

2c+4t=40
3c+5t=55

We could use substitution to solve this system of equations.
 2c+4t=40
-2c        -2c
__________
  4t=40-2c
__________
        4

t=10-1/2c

3c + 5(10-0.5c)=55
3c + 50 -2.5c = 55
      - 50.           -50
________________
        0.5c = 5
c = 10

3c + 5t = 55
3(10) + 5t = 55
 30 + 5t = 55
-30          -30
____________
      5t = 25
t = 5

So, a cd costs $10 and a cassette recording costs $5.
   
 

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