Quantitative Aptitude - Arithmetic Ability Questions

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

The co-ordinates of the centroid of a triangle ABC are (1 , -4). What are the co-ordinates of vertex C if co-ordinates of A and B are (3 , -4) and (0 , 5) respectively?

If cot π/3c -­ tan π/4c = x, then the value of x is

If a+1b = 1 and b+1c = 1 then c+1a = ?

If 3x ­- 2(4 ­- 3x) < 2x ­- 5 < 3x + 3; then the value of x is

For triangle PQR, what is the equation of altitude PS if co­ordinates of P, Q and R are (5,1), (0,­4) and (­2,3) respectively?

What is the value of 1.23+0.83+0.73-2.0161.351.22+0.82+0.72-0.96-0.84-0.56 =

If a + b = 1 and ab = -6, then what is the value of a3+ b3?