Răspuns :
2) B.30 km
x=(2/5x+3)*2 <=> x-4/5x=6 <=> 1/5x=6 <=> x=6*5 <=> x=30
3) C.10
1/2x+3x=35 <=> x=10
x=(2/5x+3)*2 <=> x-4/5x=6 <=> 1/5x=6 <=> x=6*5 <=> x=30
3) C.10
1/2x+3x=35 <=> x=10