WBCS 2021 Mains (General Studies Paper-IV) Prev. Yr. Paper (24-May-2022)

The area of a triangle, the length of whose sides are $50\text{ m}$, $78\text{ m}$ and $112\text{ m}$, is

A fisherman can row $2\text{ km}$ against the stream in $20\text{ minutes}$ and return in $15\text{ minutes}$. The speed of the boat in still water is

Gold is $19$ times as heavy as water and copper is $9$ times as heavy as water. The ratio in which these two metals are to be mixed so that the mixed alloy becomes $15$ times as heavy as water is

Direction: Read the information given below and answer the questions.
(i) In a family of six persons $\text{A, B, C, D, E}$ and $\text{F}$, there are two married couples.
(ii) $\text{D}$ is grandmother of $\text{A}$ and mother of $\text{B}$.
(iii) $\text{C}$ is wife of $\text{B}$ and mother of $\text{F}$.
(iv) $\text{F}$ is grand daughter of $\text{E}$.

Which of the following is necessarily true?