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In scoala sunt 360 elevi repartizati astfel: 2pe5 sunt in cl I,5pe9 din nr elevilir de cl I sunt in cl a ll,iar restul in celelalte 2 clase distributi in mod egal Carl elevi sunt in cl a lll?

Răspuns :

[tex]a-clasa\: I[/tex]

[tex]b-clasa\: a\: II-a[/tex]

[tex]c-clasa \:a \:III-a[/tex]

[tex]a+b+c=360[/tex]

[tex]a=\frac{2}{5}\times360[/tex]

[tex]a=\frac{2\times360}{5}[/tex]

[tex]a=\frac{720}{5}[/tex]

[tex]a=144[/tex]

[tex]b=\frac{5}{9}\times\:a[/tex]

[tex]b=\frac{5}{9}\times144[/tex]

[tex]b=\frac{5\times144}{9}[/tex]

[tex]b=\frac{5\times48}{3}[/tex]

[tex]b=5\times16[/tex]

[tex]b=80[/tex]

[tex]a+b+c=360[/tex]

[tex]144+80+c=360[/tex]

[tex]224+c=360[/tex]

[tex]c=360-224[/tex]

[tex]c=136[/tex]