At what simple rate of interest a sum is double in 8 years?

Find value of $$ {^3\sqrt{\sqrt{0.000729}}}+^3{\sqrt{0.008}}$$

What is the value of $$ {\sqrt{625}+\sqrt{484}}$$

If 3x + 7y=75, 5x- 5y= 25, then the value of (x +y)=?

2x + 4y – 8xy -1 =?

If $$ {(\sqrt {3})^{5}× {9}^{2}={3^{n}{×3\sqrt {3}}}}$$ then value of n 

The radius of the incircle of a triangle is 2 cm. If the area of the triangle is 6 cm2. Then its perimeter is -

A reduction of 20% in the price of sugar enables a housewife to purchase 6 kg. more for Rs. 240. What is the original price per kg. of sugar?