WBCS Mains 2020 Official Paper-VI

The $5\text{th}$ term in the following series:
$$a{b}^2+b{c}^2+c{d}^2+\dots \text{ to }25\text{ terms will be:}$$

If all the letters of the word RATIONALISATION are written according to the alphabetical order, which letter will be farthest from the first letter?

A and B are at a distance of $800\text{m}$. They start moving towards each other at $20\text{kmph}$ and $24\text{kmph}$ respectively. As they start, a bird sitting on the cap of A starts flying towards B, touches B and then returns towards A and so on, till they meet. What is the distance traveled by the bird, if its speed is $176\text{kmph}$?

A boat running downstream covers a distance of $16\text{km}$ in $2\text{hours}$ while for covering the same distance upstream, it takes $4\text{hours}$. What is the speed of the boat in still water?

When a number is added to seven-ninth of thirty-five per cent of $900$, the resultant is $325$. What is the number?