The average of a set of 20 numbers is P. If one of the numbers from the set is replaced with 58, then the average becomes (P - 2). What is the value of the number that is replaced?

A sum of Rs. 2000 amounts to Rs. 4000 in two years at compound interest. In how many years does the same amount becomes Rs. 8000. 

What will come in place of question mark ( ? ) in the following series?
13, 25, 61, 121, 205, ? 

 A student scored 32 % marks in science subjects out of 300. How much should he score in language papers out of 200 if he is to get overall 46 % marks? 

If 3x + 7y=75, 5x- 5y= 25, then the value of (x +y)=?

A sum of money amounted to Rs.720 in 2 years and Rs.792 in 3 years when interest is compounded annually. The annual rate of interest , (in%) is:

How many perfect squares lie between 120 and 300? 

Ranveer bought a computer paying 25% less than the list price and sold it to his neighbour at a 40% profit on his purchase cost. The profit percentage earned by Ranveer on the list price of the computer is: