If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55 and 60, then the average marks of all the students is: 

The angle of elevation of an aeroplane from a point on the ground is 60°. After flying for 15 second, the angle of elevation changes to 30°. If the Aeroplane is flying at a height of 4500 meter, then what is the speed (in m/s) of aeroplane?

Which of the following simplification value of $$ {(secA-cosA)^{2}}+{(cosecA-sinA)^{2}}-{(cotA-tanA)^{2}}$$ ?

Directions: The following graph gives Sales, Expense and Capital of a company for a period of five years 1994 to 1998. Read the graph and answer the following questions.

What was the average per annum increase in sales (in Rs. Cr.) from 1994 to 1998?

The ratio of Volume of two spheres A and B is 8 : 1. The Surface Area of Sphere B is 616 cm². Find the radius of sphere A.

A person invested 1100 in a company at compound interest compounded semi-annually. He received 1331 after one year. The rate of interest per annum is 

The total cost of x pens and (x-2) pencils is Rs 424. If one pencil and one pen costs Rs 4 and Rs 20 respectively then find x?

If there are four lines in a plane, then what cannot be the number of points of intersection of these lines?