A contractor estimates that 5 persons could plumb Ravi's house in 8 days. If he uses 6 persons instead of 5, how long should they take to complete the job.

3 Bacteria enlarged 60000 times attains a length of 3cm. What is the length of bacteria if it is enlarged 10000 times only. 4 A bus travels 40kms in 30minutes. If the speed of the bus remains same, how far can it travel in 3 hrs? 6 If a box of pens is given to 25 children, they will get 2 pens each. How many would each get, if the number of children is reduced by 10?  7 A batch of tablets were packed in 10 boxes with 6 tablets in each box. If the same batch is packed using 12 tablets in each box. How many boxes would be needed?