Răspuns:
Notam cu x creioanele negre.
[tex] \frac{10}{100} \times 38 = \frac{20}{100} \times x \\ \frac{38}{10} = \frac{x}{5} \\ x = \frac{38 \times 5}{10} \\ x = 19 \\ [/tex]
Notam cu y creioanele verzi.
[tex] \frac{10}{100} \times 38 = \frac{25}{100} \times y \\ \frac{38}{10} = \frac{y}{4} \\ y = \frac{4 \times 38}{10} \\ y = \frac{152}{10} \\ y = \frac{76}{5} [/tex]
