$A$ motor car completes a journey in $10 \, hours$. It covers the first half of the distance at $21 \, km/h$ and the remaining half at $24 \, km/h$. Find the total distance (in $km$).

$A$ and $B$ walk around a circular track. They start at $8\, a.m.$ from the same point in opposite directions. $A$ and $B$ walk at a speed of $2\, \text{rounds per hour}$ and $3\, \text{rounds per hour}$ respectively. How many times shall they cross each other before $9.30\, a.m.$?

$A$ man starts from a place $P$ and reaches the place $Q$ in $7 \, hours$. He travels $\frac{1}{4}^{th}$ of the distance at $10 \, km/h$ and the remaining distance at $12 \, km/h$. The distance,in $km$,between $P$ and $Q$ is

$A$ train travels at a speed of $10\, m/s$ and leaves Trivandrum for Nagercoil at $8\, AM$. At what distance from Nagercoil will it meet a train which leaves Nagercoil for Trivandrum at $8.20\, AM$ and travels one-third faster than the former? The distance from Trivandrum to Nagercoil is $68\, km$. (in $km$)

$A$ car travelling with $\frac{5}{7}$ of its actual speed covers $42 \, km$ in $1 \, hour \, 40 \, minutes \, 48 \, seconds.$ Find the actual speed of the car (in $km/hr$).

Walking at the rate of $4 \, km/h$, a man covers a certain distance in $2 \, \text{hours} \, 45 \, \text{minutes}$. Running at a speed of $16.5 \, km/h$, the man will cover the same distance in how many minutes?