x + y = (7 / 10 )P ;
x + y = 48 + z ;
x + y + z = P;
Combini aceste 3 relatii matematice =>
( 7 / 10 )P = 48 + P - (7 / 10 )P => (7/5)P = 48 + P => 7P = 240 + 5P => 2P = 240 => P = 120;
Atunci x + y = 84 si z = 84 - 48 => z = 36;
Dar x = y => 2x = 84 => x = 42 si y = 42;
Bafta!