A cistern which could be filled in 9 hours takes one hour more to be filled owing to a leak in its bottom. If the cistern is full in what time will the leak empty it?	Choose the most appropriate option
A) 90 B) 25 C) 40 D) 23 E) 60
1/9 - 1/x = 1/10   =&gt; 90 hrs   90NSWER 90
<result>A</result>
A cistern which could be filled in 9 hours takes one hour more to be filled owing to a leak in its bottom. If the cistern is full in what time will the leak empty it?