Quantitative Aptitude - Arithmetic Ability Questions

A box weighs 8.5 kg when full of sand and weighs 5.5 kg when it is half filled with sand . Weight of the empty box is

A bookseller bought 500 text books for  20,000. He wanted to sell them at a profit so that he get 50 books free. At what profit percent should he sell them?

On a certain principal if the Simple interest for two years is Rs 3000 and Compound interest for the two years is Rs 3225, what is the rate of Interest?

If the radius of a circumscribed circle in an equilateral triangle is 14 cm. Then what will be the radius (in cm) of the inscribed circle?

The marked price of an article is Rs. 5000. But due to a special festive offer a certain percent of discount is declared. Mr. X availed this oppurtunity and bought the article at reduced price. He then sold it at Rs. 5000 and thereby made a profit of 11 1/9%. The percentage of discount allowed was?

Which of the fractions given below, when added to 5/8, gives 1?

Mr. Rajesh buys a toy for Rs. 27.50 and sells it for Rs. 28.60. Find the gain %.

In each of the following questions two equations I and II are given. Solve both the equations and give answer:
$$\begin{gathered} I. x2+2x-195=0 \\ II. y2+30y+225=0 \end{gathered}$$