Răspunsuri

2014-03-30T10:09:37+03:00
X=nr total bile
bile rosii= \frac{1}{3} x
bile albe= \frac{3}{4} (x- \frac{1}{3} x)
bile negre=12
x= \frac{1}{3}x +  \frac{3}{4} (x- \frac{1}{3}x )+12 \\ x= \frac{x}{3} + \frac{3x}{4} - \frac{x}{4} +12 \\ x= \frac{4x}{12} + \frac{9x}{12} - \frac{3x}{12}+ \frac{144}{12}   \\ x= \frac{10x+144}{12}  \\ 12x=10x+144 \\ 2x=144 \\ x= \frac{144}{2}  \\ x=72