Lupe sold 40 tickets for a play. she sold some tickets at $3 each and other tickets at $5 each. she collected $136. how many $3 tickets did she sell

Write an equation system based on the problem. For an instance, x represents the number of $3 tickets sold and y represents the number of $5 tickets sold.
x + y = 40
3x + 5y = 136

Solve the equation system using elimination method. Use elimination of y in order to find the value of x
x + y = 40   (multiplied by 5)
3x + 5y = 136 (multiplied by 1)

5x + 5y = 200
3x + 5y = 136
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 2x        = 64
   x        = 64/2
   x        = 32
The value of x is 32. She sold 32 tickets worth $3