An ice ball melts at the rate proportional to the amount of ice at any instant. If `(2/3)rd` quantity melts in 2 hours and if initially quantity of ice is `n_0`, find the amount left after 6 hours.

The rate of decay of certain substance is directly proportional to the amount present at that instant.Initially,there are 27 gms of certain substance and three hours later it is found that 8 gms are left.Find the amount left after one more hour.

The decay rate of certain substance is directly proportional to the amount present at that instant.Initially there are 27 grams of substance and 3 hours later it is found that 8 grams left.The amount left after one more hour is……….

Radium decomposes at the rate proportional to the amount present at any time. If p percent of amount disappears in one year, what percent of amount of radium will be left after 2 years?

The rate of growth of the population of a city at any time t is proportional to the size of the population. For a certain city it is found that the constant of proportionality is 0.04. Find the population of the city after 25 years if the initial population is 10,000. [take, e =2.7182] .

The rate of increase in the numbers of bacteria culture is proportional to the number present.If initially there were 1000 bacteria and the number doubles in 1 hour,find the number of bacteria after a time of 2 1/2 hours.