mschurkina

Пусть х - количество марок в начале

х - 6 - 0.25(х - 6) - 2 = (2/3)х

х - 8 - 0.25х - 1.5 = (2/3)х

0.75х - 6.5 = (2/3)х

(3/4)х - (2/3)х = 6.5

(1/12)х = 6.5

х = 78