There is a group of five persons $A, B, C, D$ and $E$. In the group,there are a Professor of Philosophy,a Professor of Psychology,and a Professor of Economics. $A$ and $D$ are ladies who have no specialization in any subject and are unmarried. No lady is a philosopher or an economist. There is a married couple in the group of which $E$ is the husband. $B$ is the brother of $C$ and is neither a psychologist nor an economist. Who is the Professor of Economics?

$(i)$ Eleven students,$A, B, C, D, E, F, G, H, I, J$ and $K$ are sitting in the first row of the class facing the teacher.
$(ii)$ $D$,who is to the immediate left of $F$,is second to the right of $C$.
$(iii)$ $A$ is second to the right of $E$,who is at one of the ends.
$(iv)$ $J$ is the immediate neighbour of $A$ and $B$ and third to the left of $G$.
$(v)$ $H$ is to the immediate left of $D$ and third to the right of $I$.
Which of the following groups of friends is sitting to the right of $G$?

Six persons $A, B, C, D, E,$ and $F$ are standing in a circle. $B$ is between $D$ and $C$. $A$ is between $E$ and $C$. $F$ is to the right of $D$. Who is between $A$ and $F$?

Five children were administered psychological tests to know their intellectual levels. In the report,psychologists pointed out that the child $A$ is less intelligent than the child $B$. The child $C$ is less intelligent than the child $D$. The child $B$ is less intelligent than the child $C$ and child $A$ is more intelligent than the child $E$. Which child is the most intelligent?

In a car exhibition,seven cars of seven different companies viz. Cardilac,Ambassador,Fiat,Maruti,Mercedes,Bedford,and Fargo were displayed in a row,facing east such that:
$(1)$ Cardilac car was to the immediate right of Fargo.
$(2)$ Fargo was fourth to the right of Fiat.
$(3)$ Maruti car was between Ambassador and Bedford.
$(4)$ Fiat,which was third to the left of Ambassador car,was at one of the ends.
Which of the following was the correct position of the Mercedes?

The sum of the incomes of $A$ and $B$ is more than that of $C$ and $D$ taken together. The sum of incomes of $A$ and $C$ is the same as that of $B$ and $D$ taken together. Moreover,$A$ earns half as much as the sum of the incomes of $B$ and $D$. Whose income is the highest?