Quantitative Aptitude - Arithmetic Ability Questions

Twenty one times of a positive number is less than its square by 100. The value of the positive number is

What is that least number that must be added to the product 684 × 686 to make it a perfect square?

Dipali bought a set of cups for Rs. 375, but then had to sell it later to clear old stocks for Rs. 345. What is the percentage of loss that she incurred?

One-third of Poojitha's age three years ago plus one-half of her age two years from now is twenty years. How old is she now?

The prices of chairs and tables are in the ratio of 9 : 5. If the chairs cost Rs. 4200 more than the tables, find the price of the tables? (in Rs.)

The cash difference between the selling price of an article at a profit of 2% and 18% is Rs. 3. The ratio of two selling prices is

If cos 2π/3c = x, then the value of x is

What should be added to 8(3x - ­4y) to obtain 18x ­- 18y?