Answer:
The container can hold 280 liters of water.
Explanation:
Proportions
The water originally fills 1/8 of a container. Then 35 lt of water are poured into the container and now it's 1/4 full.
If we subtract the final portion of the tank minus the original portion of the container, we obtain the portion that was poured into.
If 35 liters of water is 1/8 of the tank, then it can hold 35*8 = 280 liters.
The container can hold 280 liters of water.