If $$ {x\over y}={y\over w}$$ then what is the value of (xy+zw).

If $$ {y\over x-z}={y+x\over z}={x\over y}$$ the find x:y:z is?

The ratio of the income of A to that of B is 5 : 7. A and B save Rs.4,000 and Rs.5,000 respectively. If the expenditure of A is equal to $$ {66 {2\over 3}}{\%}$$ of the expenditure of B, then the total income of A and B is:

The ratio of investment by A to that by B in a business is 14 : 15 and the ratio of their respective profit at the end of a year is 2 : 5. If A invested the money for 3 months, then for how much time ( in months) B invested his money?

If (a+b) : (b+c) : (c+a) = 7 :6 : 5 and (a+b+c)=27, then what will be the value of $$ {1\over b}:{1\over a}:{1\over c}$$.

If 8, X and 50 are in continued proportion, then the value of x is

Which of the following represents a correct proportion?