Quantitative Aptitude - Arithmetic Ability Questions

In the following question, four groups of three numbers are given. In each group the second and third number are related to the first number by a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.

In the following question, four number pairs are given. The number on left side of (–) is related to the number on the right side of (–) with someLogic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.

In the following question, four groups of three numbers are given. In each group the second and third number are related to the first number by a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one out from the given alternatives.

How much does one need to add to 4/5 to obtain 5/4?

What is the fraction which, when taken away from 1/2, gives 2/3?

Simplify 4(x-1) -3x

____ are twin prime numbers.

___ is the point at which the perpendicular bisectors of the sides meet and the center of the circle that circumscribes the triangle is ____.