benzen = C6H6 , M = 78 g/mol
antracen = C14H10 , M = 178 g/mol
avem a moli benzen + b moli antracen
masa amestec = 78a g + 178b g
78g benzen ................... 72g C
78a g .............................. X = 72a g C
178g antracen ................... 168g C
178b g .............................Y = 178b g C
100% amestec ....................................... 93,75% C
78a+178b amestec ............................. 72a+168b g C
=> 1,2b = 1,2a => a:b = 1:1
=> a.