From a container, 6 liters Solution “R” was drawn out and was replaced by water. Again 6 liters of the mixture was drawn out and was replaced by the water. Thus, the quantity of Solution “R” and water in the container after these two operations is 9:...

From a container, 6 liters Solution “R” was drawn out and was replaced by water. Again 6 liters of the mixture was drawn out and was replaced by the water. Thus, the quantity of Solution “R” and water in the container after these two operations is 9:16. The quantity of the mixture is:
a) 20 L
b) 25 L
c) 15 L
d) 10 L
e) 35 L