Verified answer

1kg = 1000g

1000g de  alcatra = R$ 7,00

100g de alcatra =  ?

                                             alcatra                             R$

                                                 1000g   ________        7

                                                     100g  ________       x

  100*7 = 1000*x

  1000*x = 100*7

   1000x = 700

        x = 700

           ______

             1000

      x =  0,70  (100g de alcatra equivale a 0,70 centavos ou R$ 0,70 )