An Aeroplan is flying horizontally at a height of 1.8 km above the ground. The angle of elevation of plane from point X is 60° and after 20 seconds, its angle of elevation from X becomes 30°, If point X is on ground, then what is the speed (in km / hr.) of Aeroplan? 

The simple and compound interest that can be earned in two years at the same rate is Rs 1500 and Rs 1575 respectively. What is the rate (% per annum) of interest?

If a cuboid of dimensions 64cm×16cm×8cm is melted and recast into two equal cubes of same size. Then what will be the ratio of the surface are of cuboid to the total surface area of the two cubes?

A person who spends $$ 16{2\over3}\% $$ of  his income is able to save 1200 per month. His monthly expenses (in) is:  

A sum become Rs. 10,650 in 5 years and Rs.11076 in 6 years at simple interest. What is the sum?

If Sonu is driving a car with a speed of 20 m/s, then in what time will Sonu cover a distance of 936 km?

Directions: The bar graph, given here, shows the number of tickets sold by 6 students A, B, C, D, E and F during a fair. 

Total number of tickets sold by D, E and F is 

If the score of five students is 8,7,9,16,25, then their mean deviation will be.