If $$ {\sqrt{3}\ CosA=SinA}$$ then what is the value of Cot A?

Four numbers are in the ratio 1 : 2 : 3 : 4 . Their sum is 16. The sum of the first and fourth number is equal to: 

$$ {4\over 5}×[{1\over 2}\ of\ 25]+12÷{3\over 4}-32=?$$

A passenger train covers the distance between stations A and B, 50 minutes faster than a goods train. Find this distance between A and B if the average speed of the passenger train is 60 km/h and that of goods train is 20 km/h?

If cos3A = X, then value of X?

If the circumradius of an equilateral triangle ABC be 8 cm, then the height of the triangle is 

The difference between CI and SI on a sum of money for 3 years at 5% per annum is Rs.61. Find the sum.