A tank is filled in 9 hours, but takes one hour longer to be filled owing to a leak. in its bottom, if the tank is full, in what time will the leak empty it ?
Answer 1
9
Answer 2
90
Answer 3
10
Answer 4
30

It takes 4 people to produce one chair in 16 hours, 8 people will take how many hours ?
Answer 1
6
Answer 2
10
Answer 3
8
Answer 4
4