Write the first four terms of the $AP,$ when the first term $a$ and the common difference $d$ are given as follows: $a=4, d=-3.$

$A$ 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 $m^3$).

$200$ logs are stacked in the following manner: $20$ logs in the bottom row,$19$ in the next row,$18$ in the row next to it and so on (see Figure). In how many rows are the $200$ logs placed and how many logs are in the top row?

In an $AP$ given $a=5, d=3, a_{n}=50,$ find $n$ and $S_{n}$.

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

In a potato race,a bucket is placed at the starting point,which is $5\, m$ from the first potato,and the other potatoes are placed $3\, m$ apart in a straight line. There are ten potatoes in the line. $A$ competitor starts from the bucket,picks up the nearest potato,runs back with it,drops it in the bucket,runs back to pick up the next potato,runs to the bucket to drop it in,and she continues in the same way until all the potatoes are in the bucket. What is the total distance the competitor has to run? (in $m$)