Two circles having radii 5 units intersect each other in such a way that each of them passes through the centre of the other. Then the length of their common chord is

Directions: The bar graph shows the results of an annual examination in a secondary school in a certain year. Answer the following four questions based on this chart.

The average number of boys passed per class is 

The sum of the digits of a 2 digit number is 9. When 27 is added to the number, the digits get interchanged. Find the number.

The ratio of speeds of A is to B is 2:3 and therefore A takes 20 minutes less time than B takes. What is the ratio of time taken by A and B?

Direction: A shopkeeper has some kg. rice of same price. He sold 150 kg. rice at 25 Rs. per kg. and earned a profit of 25%, another 180 kg. rice is sold at a profit of 20% and rest are sold at a loss of 10%. If the shopkeeper earns Rs. 1230 profit on all the rice that he has sold then answers the following question:

If the shopkeeper earns 10% profit instead of 10% loss on the rest rice then find the difference between the old and new profit. 

The length, breadth and height of a room are in the ratio 7:3:1. If the breadth and height are doubled while the length is halved, then by what percent the total area of the 4 walls of the room will be increased?

If x²+y²-4x-4y+8=0, then the value of x-y is: 

The difference between the greatest and least five-digit numbers formed by the digits 2,5,0,6,8 is (repetition of digits are not allowed)