$A$ car takes $60$ minutes less for a journey of $150\,km$,if its speed is increased by $5\,km/hr$ from its usual speed. Find the original speed of the car in $km/hr$.

$A$ rectangular park is to be designed whose breadth is $3\, m$ less than its length. Its area is to be $4\, m^2$ more than the area of a park that has already been made in the shape of an isosceles triangle with its base as the breadth of the rectangular park and of altitude $12\, m$ (see Figure). Find its length and breadth.

If one of the roots of $2x^{2}-5x+k=0$ is $\frac{7}{2}$,then $k=$ .............

Find the roots of the following quadratic equation by the method of completing the square: $x^{2}-4x-8=0$

Check whether the following is a quadratic equation:
$x^{2}+3x+1=(x-2)^{2}$

......... can be taken as the value of $k$,if one of the roots of the quadratic equation $k x^{2} - 7x + 6 = 0$ is $\frac{3}{2}$.