Răspunsuri

2014-06-24T17:37:10+03:00
F+b=120

f=20%  din b

f=20/100* b

f=1/5 *b=  b/5

b/5 +b=120   aducem la acelasi numitor

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

f=100/5
f=20
1 5 1