2.
a) a/3=5 ⇒ a=3×5=15
b/4=5 ⇒ b=4×5=20
a+b=15+20=35
b) 6/7=15/x
6x=7×15
6x=105
x=105/6=17,5
c) 60% din 200=60×200/100=60×2=120
200+120=320 lei după scumpire
3.
a) x/2=6/4
4x=12
x=12/4=3
y/3=6/4
4y=18
y=18/4=4,5
x+y=3+4,5=7,5
b) 40% din x=6
40x/100=6
40x=600
x=600/40
x=15
