...... popularized the Indian mathematics in the Middle East area.

The formula to find the sum $S$ of the first $n$ natural numbers is $S = \frac{n(n+1)}{2}$. Find $n$ if the sum of the first $n$ natural numbers is $300$.

The speed of a motorboat in still water is $25 \text{ km/hr}$. In a river, it covers $60 \text{ km}$ downstream and the same distance upstream in a total time of $5 \text{ hours}$. Find the speed of the current of the river. (The speed of the current of the river is less than the speed of the motorboat in still water.) (in $\text{ km/hr}$)

Find the roots of the quadratic equation by using the quadratic formula:
$5x^{2} + 13x + 8 = 0$

State whether the quadratic equation $(x+1)(x-2)+x=0$ has two distinct real roots. Justify your answer.

If the value of the discriminant of a quadratic equation $kx^2 - 6x + 1 = 0$ is $0$,then $k = \ldots$