Quantitative Aptitude - Arithmetic Ability Questions

The standard deviation of the set {10, 11, 9, 11, 9} is

If a merchant offers a discount of 40% on the list price, then he makes a loss of 10%. What % profit or % loss will he make if he sells at a discount of 20% of the list price?

The age of Ravi is twice the age of Prakash and three times the age of Kumar. If the age of Prakash is 24 years, then what will be the age of Kumar after 4 years ?

In what ratio sugar of Rs 38 per kg and Rs 30 per kg be mixed with each other so that on selling mixture at Rs 35.2 per kg there will be a profit of 10%?

In a class of 100 students, the average weight is 30 kg. If the average weight of the girls is 24 kg and that of the boys is 32 kg, then what is the number of girls in the class?

1 packet of biscuits costs Rs 16 but a pack of 4 of the same packet of biscuits costs Rs 56. What is the effective discount (in %) on the pack?

A sum of money is invested at 20% compound interest (compounded annually). It would fetch Rs. 723 more if interest is compounded half-yearly. The sum

Mohit sells a table at a profit of 25%. If he reduces its selling price by Rs 240, then he suffers a loss of 5%. What was the initial selling price (in Rs) of the table?