Choose the correct choice in the following and justify: $30^{th}$ term of the $AP: 10, 7, 4, \ldots$ is

Determine the $AP$ whose $3^{rd}$ term is $5$ and the $7^{th}$ term is $9$.

Find the $10^{th}$ term of the $AP : 2, 7, 12, \ldots$

$A$ small terrace at a football ground comprises of $15$ steps each of which is $50 \, m$ long and built of solid concrete. Each step has a rise of $\frac{1}{4} \, m$ and a tread of $\frac{1}{2} \, m$. Calculate the total volume of concrete required to build the terrace (in $m^3$).

Find the sum of the first $15$ multiples of $8.$

In the following $APs,$ find the missing terms in the boxes: $\square, 38, \square, \square, \square, -22$