t-pretul tortului
p-pretul prajiturii
[tex] \frac{t}{4} = \frac{p}{2} = > t = \frac{4p}{2} [/tex]
t-p=20
[tex] \frac{4p}{2} - p = 20 (aduci \: la \: acelasi \: numitor) \\ \frac{4p}{2} - \frac{2p}{2} = 20 \\ \frac{4p - 2p}{2} = 20 \\ \frac{2p}{2} = 20 \\ 2p = 2 \times 20 \\ 2p = 40 \\ p = 40 \div 2 = > p = 20[/tex]
t-p=20
t-20=20
t=20+20
t=40
un tort=40ron
trei prajituri=3×20=60ron
