Some litres of acid were drawn off a 54-litre vessel full of acid and an equal amount of water added. Again, the same volume of the mixture was drawn off and replaced by water. As a result, the vessel contained 24 litre of pure acid. How much of the acid was drawn off initially?

The difference of the circumference and radius of a circle is 37 cm. Area of the circle is

How many times the keys of a typewriter have to be pressed in order to write number from 121 to 1346?

The point P(a, b) is first reflected in origin to P1 and P1 is reflected in Y-axis to (4, -3). What are the coordinates of point P? 

What is the value of $$ {2tan53°\over cot37°} -{cot80°\over tan10°}$$ is:

A goat is tied with a 10.5 m-long rope to one corner of a plot which is in the shape of an equilateral triangle each side of which is 16 m long. Find the area that the goat can graze on.

If the sum of three dimensions and the total surface area of a rectangular box are 12 cm and 94 $$\ cm^2 $$ respectively, then the maximum length of a stick that can be placed inside the box is

If 12 men can do a piece of work in 24 days, then in how many days can 18 men do the same work?