The number of bacteria in a certain culture doubles every hour. If there were 30 bacteria present in the culture originally, how many bacteria will be present at the end of 2nd hour, 4th hour and nth hour ?

The rate of increase of bacterial in a certain culture is proportional to the number of bacterial present. If it is found that the number doubled in 5 hours, prove that the bacterial becomes eight times at the end of 15 hours.

If 15 workers can build a wall in 48 hours, how many workers will be required to do the same work in 30 hours?

In a Laboratory, the count of bacteria in a certain experiment was increasing at the rate of 2.5% per hour. Find the bacteria at the end of 2 hours if the count was initially 5, 06,000.

How many joules are present in 1 kilowatt hour?

Thirty children were asked about the number of hours they watched TV programmes in the previous week. The results were found as follows : : How many children watched television for 15 or more hours a week ?