There are three taps in a tank. Tap A can fill the tank in $3 \mathrm{hours}$ and tap B in $4 \mathrm{hours}$ while tap C can empty the tank in $8 \mathrm{hours}$. All the taps are kept open simultaneously. If the time taken to fill the tank is $x \mathrm{hours}$, then find the value of $x$ as a mixed fraction.

If $p$ persons working $p$ hours a day for each of $p$ days produce $p$ units of work, then the units of the work produced by $q$ persons working $q$ hours a day for each $q$ day is:

The cost of milk per litre is $₹15$. Draw the graph for the relation between the quantity and cost. Hence find the cost of $3$ litres of milk..

The cost of milk per litre is $₹15$. Draw the graph for the relation between the quantity and cost. Hence find the proportionality constant.

Two pipes separately take $5$ hours and $8$ hours respectively to fill a tank. The third pipe takes $3.2$ hours to drain out the water from the tank. How much time will all the three pipes take to fill the completely empty tank?