Alchohol and water in two vessels A and B are in the ratio of 5 : 3 and 5 : 4 respectively.  In what ratio the liquid of  both the vessels be mixed  to get a new mixture in the ratio of 7 : 5?

2 : 3

Vessel      Alchohal    :     Water          (Total)

     I              5    :     3    →   8 (× 9)

    II             5    :     4    →   9 (× 8)

Required       7    :     5    →  12 (× 6)

Make quantities equal and apply alligation on Alchohal    only