1. a) [tex]\frac{15}{100} *60=\frac{900}{100} =9[/tex]
b) [tex]\frac{0,25}{100}*40=\frac{10}{100}=\frac{1}{10}=0,1[/tex]
c)[tex]\frac{35}{100}*7000=35*70=2450[/tex]
2.a) [tex]\frac{18}{100}*x=90 => x=\frac{90}{\frac{18}{100} } => x=90*\frac{100}{18} =>x=5*100=>x=500[/tex]
b)[tex]\frac{23}{100}*x=4600=> x=\frac{4600}{\frac{23}{100} } => x= 4600*\frac{100}{23}=>x=200*100=>x=20000[/tex]
3. notam pretul initial al bicicletei cu x
a) [tex]x-\frac{15}{100} *x= 725-\frac{15*725}{100} =725-108,75=616,25[/tex]
b)[tex]x+\frac{10}{100} *x=725+\frac{10*725}{100} =725+72,5=797,5[/tex]
4. notam pretul initial al obiectului cu x
a) [tex]x+\frac{20}{100} *x=67200\\x+\frac{x}{5} =67200[/tex]
Amplificam pe x cu 5 si pe 67200 tot cu 5 pentru a avea numaratori egali
[tex]5x+x=67200*5\\6x=67200*5\\x=\frac{67200}{6} *5\\x=11200*5\\x=56000[/tex]
b) notam procentul necunoscut cu p
[tex]67200-\frac{p}{100}*67200 =56000\\\frac{67200p}{100} = 67200-56000\\\frac{67200p}{100} = 11200\\67200p=11200*100\\672p=11200\\p=\frac{11200}{672}\\p=16.66[/tex]
Sper ca nu am facut nicio greseala. Spor la scris <33
