1) a)1875
b)322
c)70
3) 700-x/100×700=300
700-7x=300
7x=300+700
7x=1000
x=1000:7
x=142,8571428571
2) (x,y) d.p. (9,21)
x/9=y/21=k
x/9=k=>9k
y/21=k=>21k
21k+9k=300
30k=300
k=300:30
k=10
k=9×10=90 iepe
k=21×10=210 cai
4) a) 40 capete ....................... 100%
25 capete. .......................p%
p%=25×100:40
p%=2500:40=62,5%
p%=100%-62,5%=37,5%
b)25×300:100=7500:100=75
1) a)14
b)12,17,26,35,44,53,62,71,80
