Question

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?

Answer 1

$a-clasa\: I$

$b-clasa\: a\: II-a$

$c-clasa \:a \:III-a$

$a+b+c=360$

$a=\frac{2}{5}\times360$

$a=\frac{2\times360}{5}$

$a=\frac{720}{5}$

$a=144$

$b=\frac{5}{9}\times\:a$

$b=\frac{5}{9}\times144$

$b=\frac{5\times144}{9}$

$b=\frac{5\times48}{3}$

$b=5\times16$

$b=80$

$a+b+c=360$

$144+80+c=360$

$224+c=360$

$c=360-224$

$c=136$