Quantitative Aptitude - Arithmetic Ability Questions

In the following question, select the odd word pair from the given alternatives.

If [√(a2 + b2 + ab)] + [√(a2 + b2 – ab)] = 1, then what is the value of (1 – a2 )(1 – b2 )?

In a week, how many times are the hands of a clock at right angles with each other?

2 ­- (cosA + sinA)2 is equal to

If a+1a=1,then the value of a2-a+1a2+a+1 is a≠0

Rs. x invested at 8% simple interest per annum for 5 years yields the same interest as that on Rs. y invested at 7.5% simple interest per annum for 6years. Find x : y.

Dodecahedron has 30 edges. How many vertices does it have?

Which of the following is the largest number among 2, 33, 4, 53