What is the solution -90 to the nearest integer

Suppose the # of litres in the small container is 'x'.
This would make '2x' litres of water in the larger container.
After taking 8 litres from both containers, the following equation can be written:

(2x-8) = 3 (x-8)

Open the brackets:

2x-8 = 3x-24

Collect like terms:

x = 16

There were 16 litres in the smaller container