A singular cholera bacteria produces two complete bacteria in ½ hours. If we

starts with a colony of A bacteria, how many bacteria will we have in n hours.

The enrollment of a famous school doubled after every eight years from 1970

to 1994. If the enrollment was 6000 in 1994, what was its enrollment in 1970. 

Joining the mid points of the sides of an equilateral triangle, an equilateral

triangle having half the perimeter of the original triangle is obtained. We form a

sequence of nested equilateral triangles in the manner described above with the

original triangle having parameter 3/2. What will be the total perimeter of all the

triangles formed in this way?

A man borrows Rs.1100 and agree to repay with a total interest of Rs.230 in 14

installments, each installment being less than the preceding by Rs.10 . What should be his first installment?  

 An investor earned Rs. 6000 for year 1980 and Rs. 12000 for year 1990 on the same investment. If his earning have increased by the same amount each year, how much income he has received from the investment over the past eleven years?

378 trees are planted in rows in the shape of an isosceles triangle, the numbers in successive rows decreasing by one from the base to the top. How many trees are there in the row which forms the base of the triangle?

A student saves Rs. 12 at the end to the first week and goes on increasing his saving Rs. 4 per week. After how many weeks will be able to save Rs. 2100?

A man borrows Rs.1100 and agree to repay with a total interest of Rs.230 in 14

installments, each installment being less than the preceding by Rs.10 . What should be his first installment?  

A clock strikes once when its hour hand is at one, twice when it is at two and so on. How many times does the clock strike in twelve hour? 

A man borrow Rs. 32760 without interest and agrees to repay the loan in

installment being twice the preceding one. Find the amount of the last installment, if the amount of the first installment is Rs. 8.