1)a-primul numar
b-al doilea
a+b=140
a=40% din b--->a =[tex] \frac{40b}{100} [/tex]
Inlocuim :
[tex] \frac{40b}{100} +b=140 |:100 \ \textless \ =\ \textgreater \ 40b+100b=14000\ \textless \ =\ \textgreater \ 140b=14000 |:140[/tex]
b=100
Aflam a:
a=[tex] \frac{40}{100} *100=40=\ \textgreater \ a=40[/tex]
2) Notam cu e-elevii clasei
[tex] \frac{36}{100} *e=9 \ \textless \ =\ \textgreater \ \frac{36e}{100} =9 \ \textless \ =\ \textgreater \ e= \frac{9*100}{36} =25=\ \textgreater \ e=25[/tex]
In clasa sunt 25 de elevi.
3)Notam cu x nr.probleme
[tex] \frac{15}{100} *x=12\ \textless \ =\ \textgreater \ \frac{15x}{100} =12=\ \textgreater \ x= \frac{12*100}{15} =80=\ \textgreater \ x=80[/tex]
Ca sa aflam cate mai are, facem astfel:
80-12=68
Mai are 68 probleme de rezolvat
