If the population of country double in 50 years, in how many years will it triple under the assumption that the rate of increase is proportional to the number of inhabitants.

The population P in any year t is such that the rate of increase in the population is proportional to the population. Then

if a population growing exponentially doubles in size in 3 year, what is the intrinsic rate of increase (r ) of the population ?

In a culture, the bacteria count is 1,00,000 . The number is increased by 10% in 2 hours. In how many hours will the count reach 2,00,000 if the rate of growth of bacteria is proportional to the number present ?

Find the population of a city at any time t, given that the rate of increase of population is proportional to the population at that instant and that in a period of 40 years the population increased from 3,00,000 to 4,00,000.

The half-life of radium is 1600 years. After how many years will one gram of the pure radium be reduced to one centigram?

Suppose a population control unit wants to find out "how many people will be there in a certain country after 10 years".

If the intensity of sound is doubled, by how many decibels does the sound level increase ?