If 15 is added to a number then it is increased by 20%. Find the Original number?

a. 55

b.65

c.75

d.90

e. None of the above

                 

General Aptitude question from gate.

plz visit my profile for solution.

The digits of a two-digit number differ by 3. If the digits are interchanged and the resulting number is added to the original number, the sum is 143. What is the original number?

Pick a number.  Double it. Multiply the result by 3.  Add 24. Divide by 6. Subtract your original number.  Is the result always the same? Write a convincing argument for your answer.

25. In order to obtain a small margin of error with high levels of confidence, C, you will need observations. A) a large number of B) a small number of C) 10 D) None of the above.