Răspuns :
80 % din 20 = [tex] \frac{80}{100} [/tex] x 20 = [tex] \frac{80 x 20}{100} [/tex] = 16 exercitii
20 exerc . ......100%
x ..............80 %
x =20*80/100 =16 exercitii
x ..............80 %
x =20*80/100 =16 exercitii