Ravi purchases 90 pens and sells 40 pens at a gain of 10% and 50 pens at a gain of 20%. Had he sold all of them at a uniform profit of 15% he would have got Rs. 40 less. Find the cost price of each pen.

An octahedron has 12 edges, How many vertices does it have, 

What will come in place of question mark ( ? ) in the following series?
656, 352, 200, 124, 86, ? 

Directions: Each of the questions consists of a question followed by three statements. You have to study the questions and the statements and decide which of the statements(s) is/are necessary to answer the question. 

What is the area of the hall?
 I. Material cost of flooring per sq. meter is Rs. 250
 II. labor cost of flooring the hall is Rs. 3,500
 III. Total cost of flooring the hall is Rs. 14,500

The area of trapezium is 21 square cm, the distance between the parallel sides is 3 cm and one of the parallel sides is 8.3 cm. What is the length of the other parallel side ?

Mr. Girdhar spends 50 % of his monthly income on household items and out of the remaining he spends 50% on transport 25% on entertainment, 10% on sports and remaining amount of Rs.900 is saved. What is Mr.Giridhar's monthly income? 

Study the following graph and answer the question that follow.

What is the approximate average number of candidates passed from all the institutes together?