Răspunsuri

2014-06-17T11:09:20+03:00
F+b=120

f=20% din b=  20/100* b=   1/5 * b=   b/5

b/5 +b =120  aducem la acelasi numitor

b+5b=600
6b=600
b=100

f=100/5=20


2014-06-17T14:46:31+03:00
Notam cu f=femei
b=barbati
f+b=120

f=20% x b= \frac{20}{100}  =  \frac{1}{5} b

 \frac{b}{5}  +b =120  
b+5b=600
6b=600
b=100

f= \frac{100}{5} =20