To solve this problem, all we have to do is to thoroughly analyze the situation step by step.
First let us work on the remaining 10 gallons of water in the tank. We are given that 2 / 3 of the water initially in the tank leaked out. Therefore this means that we are left with 1 / 3 the original amount of water which is 10 gallons, hence:
(1 / 3) Vi = 10 gallons
where Vi is the initial volume of water inside the tank, calculating for Vi:
Vi = 3 (10 gallons)
Vi = 30 gallons
We are also given that this initial volume of water is just 3 / 4 of the total capacity of the tank, therefore:
(3 / 4) Vc = Vi
where Vc is the volume capacity of the tank, calculating for Vc:
Vc = 4 Vi / 3
Vc = 4 (30 gallons) / 3
Vc = 40 gallons
Answer:
Capacity of the fish tank is 40 gallons