The cistern is losing approximately 3.963 gallons of water per hour.
<u><em>Explanation</em></u>
A cistern is leaking 0.25 liters of water per minute.
<u>We know, 1 gallon = 3.785 liters</u>
So, 0.25 liters = gallons
That means, the cistern is losing 0.06605....gallons of water per minute.
So, the amount of water losing in 1 hour or 60 minutes <em>(Approximately)</em>