If angle bisector of a triangle bisects the opposite side, then what type of triangle is it?

Area of the triangle formed by the graph of the straight lines x - y = 0, x + y = 2 and the x-axis is: 

If one root of the equation $$ {Ax^2+Bx+C=0}$$ is two and a half times the others, then which of the following is True?

A can complete a piece of work in 18 days, B in 20 days and C in 30 days. B and C together start the work and are forced to leave after 2 days. The time taken by A alone to complete the remaining work is?

What is the value of $$ {\sqrt{625}+\sqrt{484}}$$

From a point 20 m away from the foot of a tower, the angle of elevation of the top of the tower is 30°. The height of the tower is

The average of 6 numbers is 20. If a number is removed then average becomes 15. In place of removed number by adding a number 39 the average of new 6 number will be__

In a class, there are 30 girls and 15 boys and total average weight of class is $$47{7\over15}$$ kg. The total average weight of boys is 58 kg. Find the approximate average weight of girls.