Two towns $\mathrm{A}$ and $\mathrm{B}$ are $60 km$ apart. A school is to be built to serve $150$ students in town$A$ and $50$ students in town $B$. If the total distance to be travelled by all $200$ students is to be as small as possible, then the school should be built at :

Four different candles, which can last for 5 hours, 4 hours, 3 hours, 2 hours of burning, respectively, are lit in a room at the same instant and allowed to burn till such time that the three candles in the room get extinguished. The cost of burning each one of these candles is 75 paise per hour. The cost involved is :

The following table shows the percentage change in the consumption of electricity by five towns P, Q, R, S, and T from $1986$to $1988$:

In town T, where $50,000$ units were consumed in $1986$, how much did it consume in $1988$?