A person bought pens at 25 for a rupee and sold at 15 for a rupee. What is his profit percentage? 

In how many different ways can the letters of the word ‘STRESS’ be arranged?

Suresh, Dinesh and Ramesh became partners in a business by investing money in the ratio of 3 : 6 : 8. If their investments is increased by 5%, 15% and 20%, respectively, then what will be the ratio of their profits for one year? 

What must be added to two numbers that are in the ratio of 3:4, so that they become in the ratio 4:5?

16 children are to be divided into two group A and B consisting of 10 and 6 children. The average percent marks obtained by the children of Group A is 75 and the average percent marks of all the 16 children is 76. What is the average percent marks of children of Group B?

A and B under took a work Rs 2200. A alone can do the work in 10 days and B alone can do the work in 12 days. If they work together, then what will be the difference (in Rs) in the amount they receive?  

The value of $$ {4^{10+n}}.{16^{3n-4}}\over4^{7n}$$ is:

If the number 247_679 is completely divisible by 9, then the smallest whole number in the place of the blank digit will be