Since 480ml of water being used led to the volume in Container A to decrease to 1/5 from full, we can determine that the vol. left in Container A is 120ml.
When 5/8 of water is poured from B to A, water in A became 580ml
5/8 of water from B = 580 – 120 (original amount in A) =460
amount of water in B at first is 8/8, so (460/5)x8=736