\frac{300-250}{250}*100\% = \frac{50}{250}*100\% = 20\%
\frac{250-200}{ 250}*100\% = \frac{50}{ 250}*100\% = 20\%
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albo:
250zł--------100%
300-250zł-----x [%]
---------------------------z proporcji:
250x=100*50
x=5000/250
x=20[%]
II zadanie tak samo
250zł-----100%
50zł------x %
-------------
…
x=20%