Quantitative Aptitude - Arithmetic Ability Questions

If x + y = 12 and x2 + y2 = 94, then xy is 

In the following question, select the odd number from the given alternatives.

The reciprocal of the sum of the reciprocals of 2/9 and 7/10 is

What is the average of all natural numbers from 21 to 39?

If a(x + y) = b(x - y) = 2ab, then the value of 2(x2 + y2)

The circumferences of two circles are touching externally. The distance between their centres is 12 cm. The radius of one circle is 7 cm. Find the diameter(in cm) of the other circle.

The area of an equilateral triangle is 25√3 sq.cm. Find its side (in cm).

If x = 3+13, then the value of x-12642x-1x-233 is