Răspuns :
[tex] \frac{80}{100} * x = 2400\\ \\\frac{80x}{100} = 2400\\\\\frac{8x}{10} = 2400\\\\ 8x = 10 * 2400\\\\ 8x = 24000\\\\ x = 24000 : 8\\\\ x = 3000\\\\\\\frac{30}{100} * x = 900 [/tex]
80% din a = 2 400
80 a / 100 = 2 400
80 a = 240 000
a = 240 000 : 80
a = 3 000 → numarul
Verific: 80 % din 3 000 ⇒ 3000 : 100 x 80 = 2 400