WBCS Mains 2020 Official Paper-VI

Suppose milk is sold at the rates of $5.50$, $6.00$, $5.75$ and $5.25$ rupees per litre in four different months. Assuming that equal amount of money are spent on milk by a family in the four months, the average price in rupees per litre will be:

A car is running first $5\text{ kilometers}$ at a speed of $40\text{km/hr}$, next $20\text{ kilometers}$ at $60\text{km/hr}$ and then another $30\text{ kilometers}$ at $50\text{km/hr}$ speed. Then the average speed of the car is:

A problem is given to three students whose chances of solving it are $\frac{1}{2}$, $\frac{1}{3}$ and $\frac{1}{4}$ respectively. What is the probability that the problem will be solved?

In one hour, a boat goes $11\text{km}$ along the stream and $5\text{km}$ against the stream. The speed of the boat in still water (in $\text{km/hr}$) is:

A tap can fill a bucket in $6\text{hours}$. After half the bucket is filled, three more similar taps are opened. What is the total time taken to fill the bucket completely?