Răspuns :
X/Y = 2/5 ==> X = 2Y/5
2X+5X/3X+8Y =
= (4Y/5+10Y/5)/(6Y/5+8Y) =
= 14Y/5 / (6Y+8Y×5)/5 =
= 14Y/5 / (6Y+40Y/5) =
= 14Y/5 × 5/46Y =
= 14Y/46Y =
= 7/23
2X+5X/3X+8Y =
= (4Y/5+10Y/5)/(6Y/5+8Y) =
= 14Y/5 / (6Y+8Y×5)/5 =
= 14Y/5 / (6Y+40Y/5) =
= 14Y/5 × 5/46Y =
= 14Y/46Y =
= 7/23