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

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 growth of a population is proportional to the number present. If the population of a colony doubles in 50 years, in how many years will the population become triple?

If NAV of one unit is Rs 25 , then how many units will be alloted for the investment of Rs 10,000?

Suppose that five people are ill during the first week of an epidemic and each sick person spreads the contagious disease to four other people by the end of the second week and so on. By the end of 15th week, how many people will be affected by the epidemic?

Out of 10 consonants and 4 vowels, how many words can be formed each containing 3 consonants and 2 vowels ?

A village has 4000 literate people in the year 2010 and this number increases by 400 per year. How many literate people will be there till year 2020?