(A) Let the cost of a bat be $x$ and the cost of a ball be $y$.
According to the given information:
$7x + 6y = 3800$ $...(1)$
$3x + 5y = 1750$ $...(2)$
From equation $(1)$,we express $y$ in terms of $x$:
$6y = 3800 - 7x$
$y = \frac{3800 - 7x}{6}$ $...(3)$
Substituting this value of $y$ into equation $(2)$:
$3x + 5\left(\frac{3800 - 7x}{6}\right) = 1750$
Multiply the entire equation by $6$ to simplify:
$18x + 5(3800 - 7x) = 10500$
$18x + 19000 - 35x = 10500$
$-17x = 10500 - 19000$
$-17x = -8500$
$x = 500$
Now,substitute $x = 500$ into equation $(3)$:
$y = \frac{3800 - 7(500)}{6}$
$y = \frac{3800 - 3500}{6}$
$y = \frac{300}{6} = 50$
Therefore,the cost of one bat is ₹ $500$ and the cost of one ball is ₹ $50$.