1) x pretul initial a cheltuit 30% inseamna:30x/100 rest:x-30x/100=(100x-30x)/100=70x/100 a cheltuit 2/7 din rest inseamna: 70x/100·2/7 simplificam cu 7=20x/100 rest:70x/100-20x/100=50x/100 50x/100=1800 50x=1800·100 x=180000/50 x=3600 lei pretul initial verificare 3600·30/100=1080 lei a cheltuit 3600-1080=2520 lei rest 2520·2/7=720 lei a cheltuit 2520-720=1800 lei rest 2) x+y=156 x/y=5/7 7x=5y x=5y/7 inlocuim in prima relatie 5y/7+y=156 (5y+7y)/7=156 12y/7=156 y=156·7/12 y=91 x=5·91/7 x=65