Question

repede!!! va rog!!!

Answer 1

Ex. 4
a)$\frac{23}{50} + \frac{39}{50} - \frac{12}{50} = \frac{50}{50}= 1$
b)$3 \frac{4}{5} -1 \frac{3}{10} - \frac{4}{15} = \frac{19}{5} ^{6} - \frac{13}{10}^{3} - \frac{4}{15} ^{2} = \frac{114}{30} - \frac{39}{30} - \frac{8}{30} = \frac{67}{30} =2 \frac{7}{30}$
c)nu stiu
Ex. 5
meri-?,$\frac{5}{9}$
peri-?,35% din rest
ciresi-?, restul
copaci-360
                                          Rezolvare:
a)360÷9×5=200-meri
b)(360-200)×35%=160×35÷100=56-peri
c)360-200-56=134- ciresi

Ex. 6
x=lungime drum
20%x=$\frac{x}{5}$=ziua 1
$\frac{x-x}{5}= \frac{4x}{5} = rest$
$\frac{4x}{5}$×0.5=$\frac{4x}{5}$×$\frac{1}{2}$=$\frac{2x}{5}$=ziua 2
140 km=ziua 3

$\frac{x}{5}+ \frac{2x}{5}$+140=x
$\frac{3x}{5}$+140=x
3x+700=5x
2x=700
x=350 km
 
Ex.7
y=lei Carmen
x=lei Dana
z=lei camelia
$12 \frac{1}{2}$ = 12,5 lei
$\frac{175}{10}$=17,5 lei
y+x+z=83
y-12,5 = x-15,5=z-17,5
83-(12,5-15,5-17,5)= 83-45,5=37,537,5:3=12,5 lei 
y=12,5+12,5=25 lei
x=12,5+15,5=28 lei
z=12,5+17,5=30 lei