Quantitative Aptitude - Arithmetic Ability Questions

Which of the following numbers is not a prime number?

The sum of digits of a two-digit number is 9. When the digits are reversed, the number decreases by 45. Find the changed number.

In a mixture of 45 litres, the ratio of liquid A and liquid B is 7 : 2. If 11 litres of liquid B is added to the mixture, then what will be the ratio of liquid A and liquid B in the new mixture?

Of the three numbers, the average of the first number and the second number is 37 more than the average of second number and third number. What is the difference between the first and the third number?

Of the 3 numbers whose average is 112, the first is 3/13 times the sum of other 2. The first number is _____.

If a2+1=9a, (a≠0) then the value of a2+1a2 is

In an alloy, aluminium and tin are in the ratio of 4 : 5. In the second alloy, the ratio of same elements is 4 : 7. If equal quantities of these two alloys be mixed to form a new alloy, then what will be the ratio of both of these elements in the new alloy?

What is the area (in square units) of the figure enclosed by the x-axis, the y-axis and the line x + 2y = 6 ?