Cost of a diamond varies directly as the square of its weight. A diamond broke into four pieces with their weights in the ratio 1 : 2 : 3: 4. If the loss in the total value of the diamond was Rs.7000, the price of the original diamond was

At what percent per annum will Rs. 3000 amounts to Rs. 3993 in 3 years if the interest is compounded annually?  

Speed of a boat in still water is 6 km/hr and speed of the current is 2 km/hr. If boat takes four hours more in upstream than in the downstream to cover ‘D’ km, then find time take by boat to cover ‘D’ km in still water?

If $$ sin(θ+30^0)= {3\over \sqrt { 12} }  $$ then find cos²θ : 

The sum of two positive numbers is 20% of the sum of their squares and 25% of the difference of their squares. If the numbers are x and y then, is equal to

A sum of ₹ 3000 yields an interest of ₹ 1080 at 12% per annum simple interest in how many years ?

A boat can row 15 km per hour downstream and 9 km per hour upstream. The speed (in km/hour) of the boat in still water is:

Directions : What will come in the place of the question mark (?) in the following number series?

1  2  6  15  31  ?