Question

Sa se afle varstele a doua surori Corina si Cristina stiind ca acum 3 ani varsta Corinei era de 3 ori ma mare decat diferenta varstelor lor,iar peste 5 ani,suma varstelor va fi de 3 ori mai mare decat varsta actuala a Cristinei. ( varsta Corinei este mai mare decat varsta Cristinei. )

Answer 1

$x \leftarrow varsta \ Corinei \\ y \leftarrow varsta \ Cristinei \\\\ x-3=3((x-3)-(y-3)) \\\\ x-3=3(x-3-y+3) \\\\ x-3=3(x-y) \\\\ x-3=3x-3y \\\\ x-3x=-3y+3 \\\\ -2x=-3y+3 \\\\ x=\frac{3y-3}{2} \\\\\\\ x+5+y+5=3(y-5) \\\\ x+y+10=3y-15 \\\\ y-3y=-15-10-x \\\\ -2y=-x-25 \\\\ 2y=x+25 \\\\\\ 2y^{(2}=\frac{3y-3}{2}+25^{(2} \\\\ 4y=3y-3+50 \\\\ 4y-3y=47 \\\\ \boxed{y=47 \ ani \ are \ Cristina} \\\\\\ x=\frac{47*3-3}{2} =\frac{141-3}{2}=\frac{138}{2} =69 \\\\ \boxed{x=69 \ ani \ are \ Corina}$