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Radu pleaca in vacanta.In prima zi parcurge 3/10 din drum,a doua zi parcurge 4/7 din drumul ramas,iar a treia zi a parcurs cei 450 km ramasi pana la destinatie.Afla lungimea drumului parcurs de Radu pana la destinatie.(metoda mersului invers)


Răspuns :

drumul are 10 parti din 10, 10/10

I zi, parcurge 3/10,  10/10-3/10=7/10 raman de parcurs

II zi,  parcurge 4/7 din 7/10=4/7 x 7/10= (4x7)/(7x10) = 4/10 parcurge,

III zi 450 km care reprezinta conform graficului 3/10

/--------/--------/---------/---------/---------/---------/---------/---------/---------/---------/
{.............3/10.............}
                                 {...4/7din rest=4/10din drum...} {.........450km..........}

1 segment = 450:3=150

  I zi 150x3=450km
 II zi 150x4=600km
III zi 150x3=450km