 Hi and welcome to our session. Let us discuss the following question. The question says 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 second hour, fourth hour and in it are? Let's now begin with the solution. Since the number of bacteria in a certain culture doubles every hour, therefore number of bacteria present in the culture form a GP since the ratio remains the same and that is 2. Now according to the first statement of the question the number of bacteria in a certain culture doubles every hour. That means after every hour number of bacteria gets doubled. That means the number of bacteria forms a GP whose common ratio is 2. So number of bacteria present in the culture of a GP, number of bacteria present initially so this means first term of this GP that is A is 30 and R that is common ratio is equal to 2. Now bacteria present after 1 hour will be double of the bacteria present initially. So this means number of bacteria present after 1 hour will be equal to AR and this is equal to 30 into 2 which is equal to 60. Now the bacteria present will be double of the bacteria present after 1 hour and this means AR will now be equal to AR square and this is equal to 30 into 2 square and this is equal to 120. For in the same pattern bacteria present after 4 hours is equal to A into R to the power 4 and this is equal to 30 into 2 to the power 4 and this is equal to 480 and bacteria present to N hours is equal to A into R to the power N and this is equal to 30 into 2 to the power N. Hence I required answer is 120, 480, 30 into 2 to the power N. This completes this session. Bye and take care.