Quantitative Aptitude - Arithmetic Ability Questions

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

The average of 17 results is 60. If the average of first 9 results is 57 and that of the last 9 results is 65, then what will be the value of 9th result?

If there are four lines in a plane, then what cannot be the number of points of intersection of these lines?

The diagonal of a square is equal to the side of an equilateral triangle. If the area of the square is 15√3 sq cm, what is the area of the equilateral triangle?

The variance of a set of data is 121. Then the standard deviation of the data is

The length of a mirror arc is 2/9 of the circumference of the circle. Write the measure of the angle (in degrees) subtended by the arc at the centre of the circle.

Find the value of 'a' for which x+3x+a24 is a perfect square.

72% of a number is 90. What is the number?