\frac{a^{1/2} + a^{-1/2}}{1 - a} + \frac{1 - a^{-1/2}}{1 + \sqrt{a}} is equal to:

If A, B and C enter into partnership with shares in the ratio \frac{7}{2}:\frac{4}{3}:\frac{6}{5}. After 4 months, A increase his share by 50%. If the…

What proportion of water must be added to milk to gain 20% by selling it at the cost price ?

The ratio of compound interest and simple interest on a certain sum at the rate of 4% per annum for 2 years is :