22. A can
contains a mixture of two liquids A and B in the ratio 7:5 when 9 liters of
mixture are drawn off and the can is filled with B,the ratio of A and B becomes
7:9. How many liters of liquid A was contained by the can initially?
Solution:
Suppose
the can initially contains 7x and 5x liters
of
mixtures A and B respectively .
Quantity
of A in mixture left = (7x- (7/12)*9 )lit
=
7x - (21/4) liters.
Quantity
of B in mixture left = 5x - 5/12*9
=
5x - (15/4) liters
Therefore
(7x – 21/4)/ (5x – 15/4+9)=7/9
(28x-21)/(20x
+21)= 7/9
(252x
-189)= 140x +147
112x
= 336
=>
x=3.
So
the can contains 21 liters of A.
