An empty tank is filled by a pipe in 2 hours, whereas an another pipe empties the full tank in 3 hours. If the tank is empty and both the pipes are opened together the tank will be filled in:

1. 5 hours

2. 1 hour

3. 6 hours

4. none of these

A can do a piece of work in 'x' days and B can do the same work in (x + 16) days. If both working together can do it in 15 days; calculate 'x'.

A trader bought an article for ₹ x and sold it for ₹ 52, thereby making a profit of (x - 10) percent on his outlay. Calculate the cost price.

The C.P. of an article is ₹ x which is sold for ₹ 27 at a loss of (x - 5) percent; find the value of x.