A train is 125 m long. If the train takes 30 seconds to cross a tree by the railway line, then the speed of the train is:

The angle of elevation of sun changes form 30°to 45°, the length of the shadow of a pole decreases by 4 meters, the height of the pole is (Assume √3 = 1.732) 

Three pipes A, B and C can fill a cistern in 6 hours. After working at it together for 2 hours, C is closed and A and B can fill the remaining part in 7 hours. The time taken by C alone to fill the cistern is_

The compound interest earned in two years at 8 % per annum is 3993.6 . What is the sum invested? 

Three sets of English, Mathematics and Science books containing  336, 240, 96 books respectively have to be stacked in such a way that all the books are stored subject wise and the height of each stack is the same. Total number of stacks will be: 

Find the value of 13/16 share of land whose 9/7 share is worth 10,116.

A can make a cupboard in 20 days and B can do it in 60 days . Along with C , they did the job in 10 days only . Then in how many days C alone can do the job ? 

A root of equation $$({ax}^2+bx+c)$$ (where a, b and c are rational numbers) is 5 +3√3. What is the value of $$({a}^2+b^2+c^2) / (a+b+c) ? $$