Evaluate: $$ {9।3-5।-5।-5।4।÷10\over-3(5)-2×4÷2}$$

In an exam, 3 marks are scored on the correct solution, but 2 marks are deducted on the wrong solution. If a student scores 75 questions and gets 75 marks, the correct answer is the number of questions.

A tank can be filled by A in 60 minutes and emptied by B in 75 minutes. The tank is half filled and Ravi wants to fill the tank but opens B mistakenly and realizes after half hour and closed tap B. He then opens A and tank is completely filled in _______ minutes.

If a number is increased by 30 % and after that it is decreased by 25 % and again it is increased by 25 % then find average change in percentage? (approx.) 

ABCD is square and CDE is an equilateral triangle outside the square . What is the value ( in degrees ) of ∠BEC ? 

A conical vessel of radius 6 cm and height 8 cm. is completely filled with water. A sphere is lowered into the water and its size is such that when it touches the sides, it is just immersed. The fraction of water that overflows is? 

Directions: The following table represents the percentage marks of four students in six subjects.
Consider the table and answer questions based on it

The average marks obtained by the students in Geography and History are

If $$ {x^2-12x+33=0}$$, then what is the value of $${(x-4)^2+[{1\over({x-4})^2}}]$$.