1.
1)
a) 0.205=205/1000=41/200
b)1,0(21)=(1021-10)/990=1011/990=337/330
2)
a)9/2=4.5
b)19/12=1.58(3)
3)
Ma=(3.25+2.35)/2
Ma=2.8
4)
2.1x+1.2<7.5
2.1x<6.3
x<3
x=0 sau 1 sau 2
R=3
2.
1)
a)(0.8+4*(0.34*10+1.2:2)):0.168=
=(0.8+4*(3.4+0.6)):0.168=
=(0.8+4*4):0.168=
=(0.8+16):0.168=
=16.8+0.168=
=16.968
b)1.5*(6.4+2.2*(3.1 la 2-4.61)):2=
=1.5*(6.4+2.2*(9.61-4.61)):2=
=1.5*(6.4+2.2*5):2=
=1.5*(6.4+11):2=
=1.5*17.4:2
=26.1:2=
=13.05
2)
roșii : 1kg ........ 2.5 lei
1.75 ....... R lei
R=(1.75*2.5)/1 lei
R=4.375 lei
cartofi : 1kg ....... 1.3 lei
3.5kg ....... C lei
C=3.5*1.3 lei
C=4.55 lei
mere : 1kg ........3.50 lei
3kg ........ M lei
M=3*3.50
M=10.5 lei
4.375+4.55+10.5=19.42 lei
50-19.42= 30.58 lei
A primit rest 30.58 lei
3)
x-lungimea drumului
În prima zi: x/2+1
A doua zi: 1/3 * (x/2+1) +1
A treia zi: 3km
x/2+1+1/3*(x/2+1)+1+3=x
x/2+1+x/6+1/3+1+3=x
x/2+x/6-x=-1-1/3-1-3
(3x+x-6x)/6=-5-1/3
-2x/6=(-15-1)/3
-2x/6=-16/3
2x/6=16/3
6x=96
x=16km
4)
3.44x-6.14=8.16+1.24x
3.44x-1.24x=8.16+6.14
2.2x=14.3
x=6.5
3.4 <egal 2x+1 <egal 5.6
2.4 <egal 2x <egal 4.6
1.2 <egal x <egal 2.3
x=2
5)
x-preț inițial
x-15x/100=25.5
85x/100=25.5sâ
85x=2550
x=30 lei
