169)
x=suma initiala
3x=x/2+50
6x=x+100
5x=100
x=20 lei
I-----I-----I suma initiala
I-----I-----I-----I-----I-----I-----I suma triplata
I-----I jumatate din suma initiala
I-----I-----I-----I-----I-----I diferenta dintre 1/2 din suma initiala si suma triplata =50
50:5=10 lei =jumatate din suma initiala
10 ×2=20 lei suma initiala
170)
x=nr servetele initial
2x=2x/5+24
10x=2x=120
8x=120
x=15 servetele
I----I----I----I----I----I nr servetele initial
I----I----I----I----I----I----I----I----I----I----I nr servetele dublate
I----I----I 2/5 din servetele
I----I----I----I----I----I----I----I----I dif.dintre nr servetele dublate si 2/5 din servetele=24
24:8=3
3×5=15 servetele initial
171)
x=nr initial de masinute
x/4=x/2-10
x=2x-40
x=40 masinute
I----I----I----I----I nr masinute initial
I----I nr masinute micsorate de 4 ori
I----I----I jumatate din masinute initial
I----I dif.dintre 1/2 masinute initial si nr masinute miscorate de 4 ori =10
10×4=40 masinute initial