Çözüldü Profit - Loss Problem

If a stationery store sells some sort of pencils for eighty kuruses each then a profit of three liras is made, but a loss of four liras fifty for fifty five kuruses each, how many pencils does the store have?
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Let there be x amount of pencils initially purchased by the store totally for P liras.
From the equations 0.8x - P = 3 and 0.55x - P = -4.5; x = 30 (solution left for the interested students)