Răspuns:
[tex]x/100*140=28\\\\140x=28*100\\\\x=2800:140\\\\x=20[/tex]
x/100 × 140=28
140x/100=28
28 il amplificam cu 100 si vom avea 100×28=2800
=> 140x/100=2800/100
=>140x=2800
=>x=2800÷140
=>x=20%
